------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C H 4 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2024, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING3. If not, go to -- -- http://www.gnu.org/licenses for a complete copy of the license. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Accessibility; use Accessibility; with Aspects; use Aspects; with Atree; use Atree; with Debug; use Debug; with Diagnostics.Constructors; use Diagnostics.Constructors; with Einfo; use Einfo; with Einfo.Entities; use Einfo.Entities; with Einfo.Utils; use Einfo.Utils; with Elists; use Elists; with Errout; use Errout; with Exp_Util; use Exp_Util; with Itypes; use Itypes; with Lib; use Lib; with Lib.Xref; use Lib.Xref; with Mutably_Tagged; use Mutably_Tagged; with Namet; use Namet; with Namet.Sp; use Namet.Sp; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Output; use Output; with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Aux; use Sem_Aux; with Sem_Case; use Sem_Case; with Sem_Cat; use Sem_Cat; with Sem_Ch3; use Sem_Ch3; with Sem_Ch6; use Sem_Ch6; with Sem_Ch8; use Sem_Ch8; with Sem_Dim; use Sem_Dim; with Sem_Disp; use Sem_Disp; with Sem_Dist; use Sem_Dist; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; with Sem_Type; use Sem_Type; with Sem_Util; use Sem_Util; with Sem_Warn; use Sem_Warn; with Stand; use Stand; with Sinfo; use Sinfo; with Sinfo.Nodes; use Sinfo.Nodes; with Sinfo.Utils; use Sinfo.Utils; with Snames; use Snames; with Style; use Style; with Tbuild; use Tbuild; with Uintp; use Uintp; with Warnsw; use Warnsw; package body Sem_Ch4 is -- Tables which speed up the identification of dangerous calls to Ada 2012 -- functions with writable actuals (AI05-0144). -- The following table enumerates the Ada constructs which may evaluate in -- arbitrary order. It does not cover all the language constructs which can -- be evaluated in arbitrary order but the subset needed for AI05-0144. Has_Arbitrary_Evaluation_Order : constant array (Node_Kind) of Boolean := (N_Aggregate => True, N_Assignment_Statement => True, N_Entry_Call_Statement => True, N_Extension_Aggregate => True, N_Full_Type_Declaration => True, N_Indexed_Component => True, N_Object_Declaration => True, N_Pragma => True, N_Range => True, N_Slice => True, N_Array_Type_Definition => True, N_Membership_Test => True, N_Binary_Op => True, N_Subprogram_Call => True, others => False); -- The following table enumerates the nodes on which we stop climbing when -- locating the outermost Ada construct that can be evaluated in arbitrary -- order. Stop_Subtree_Climbing : constant array (Node_Kind) of Boolean := (N_Aggregate => True, N_Assignment_Statement => True, N_Entry_Call_Statement => True, N_Extended_Return_Statement => True, N_Extension_Aggregate => True, N_Full_Type_Declaration => True, N_Object_Declaration => True, N_Object_Renaming_Declaration => True, N_Package_Specification => True, N_Pragma => True, N_Procedure_Call_Statement => True, N_Simple_Return_Statement => True, N_Has_Condition => True, others => False); ----------------------- -- Local Subprograms -- ----------------------- procedure Analyze_Concatenation_Rest (N : Node_Id); -- Does the "rest" of the work of Analyze_Concatenation, after the left -- operand has been analyzed. See Analyze_Concatenation for details. procedure Analyze_Expression (N : Node_Id); -- For expressions that are not names, this is just a call to analyze. If -- the expression is a name, it may be a call to a parameterless function, -- and if so must be converted into an explicit call node and analyzed as -- such. This deproceduring must be done during the first pass of overload -- resolution, because otherwise a procedure call with overloaded actuals -- may fail to resolve. procedure Analyze_Operator_Call (N : Node_Id; Op_Id : Entity_Id); -- Analyze a call of the form "+"(x, y), etc. The prefix of the call is an -- operator name or an expanded name whose selector is an operator name, -- and one possible interpretation is as a predefined operator. procedure Analyze_Overloaded_Selected_Component (N : Node_Id); -- If the prefix of a selected_component is overloaded, the proper -- interpretation that yields a record type with the proper selector -- name must be selected. procedure Analyze_User_Defined_Binary_Op (N : Node_Id; Op_Id : Entity_Id); -- Procedure to analyze a user defined binary operator, which is resolved -- like a function, but instead of a list of actuals it is presented -- with the left and right operands of an operator node. procedure Analyze_User_Defined_Unary_Op (N : Node_Id; Op_Id : Entity_Id); -- Procedure to analyze a user defined unary operator, which is resolved -- like a function, but instead of a list of actuals, it is presented with -- the operand of the operator node. procedure Analyze_One_Call (N : Node_Id; Nam : Entity_Id; Report : Boolean; Success : out Boolean; Skip_First : Boolean := False); -- Check one interpretation of an overloaded subprogram name for -- compatibility with the types of the actuals in a call. If there is a -- single interpretation which does not match, post error if Report is -- set to True. -- -- Nam is the entity that provides the formals against which the actuals -- are checked. Nam is either the name of a subprogram, or the internal -- subprogram type constructed for an access_to_subprogram. If the actuals -- are compatible with Nam, then Nam is added to the list of candidate -- interpretations for N, and Success is set to True. -- -- The flag Skip_First is used when analyzing a call that was rewritten -- from object notation. In this case the first actual may have to receive -- an explicit dereference, depending on the first formal of the operation -- being called. The caller will have verified that the object is legal -- for the call. If the remaining parameters match, the first parameter -- will rewritten as a dereference if needed, prior to completing analysis. procedure Check_Misspelled_Selector (Prefix : Entity_Id; Sel : Node_Id); -- Give possible misspelling message if Sel seems likely to be a mis- -- spelling of one of the selectors of the Prefix. This is called by -- Analyze_Selected_Component after producing an invalid selector error -- message. procedure Find_Arithmetic_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id); -- L and R are the operands of an arithmetic operator. Find consistent -- pairs of interpretations for L and R that have a numeric type consistent -- with the semantics of the operator. procedure Find_Comparison_Equality_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id); -- L and R are operands of a comparison or equality operator. Find valid -- pairs of interpretations for L and R. procedure Find_Concatenation_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id); -- For the four varieties of concatenation procedure Find_Boolean_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id); -- Ditto for binary logical operations procedure Find_Negation_Types (R : Node_Id; Op_Id : Entity_Id; N : Node_Id); -- Find consistent interpretation for operand of negation operator function Find_Primitive_Operation (N : Node_Id) return Boolean; -- Find candidate interpretations for the name Obj.Proc when it appears in -- a subprogram renaming declaration. procedure Find_Unary_Types (R : Node_Id; Op_Id : Entity_Id; N : Node_Id); -- Unary arithmetic types: plus, minus, abs procedure Check_Arithmetic_Pair (T1, T2 : Entity_Id; Op_Id : Entity_Id; N : Node_Id); -- Subsidiary procedure to Find_Arithmetic_Types. T1 and T2 are valid types -- for left and right operand. Determine whether they constitute a valid -- pair for the given operator, and record the corresponding interpretation -- of the operator node. The node N may be an operator node (the usual -- case) or a function call whose prefix is an operator designator. In -- both cases Op_Id is the operator name itself. procedure Diagnose_Call (N : Node_Id; Nam : Node_Id); -- Give detailed information on overloaded call where none of the -- interpretations match. N is the call node, Nam the designator for -- the overloaded entity being called. function Junk_Operand (N : Node_Id) return Boolean; -- Test for an operand that is an inappropriate entity (e.g. a package -- name or a label). If so, issue an error message and return True. If -- the operand is not an inappropriate entity kind, return False. procedure Operator_Check (N : Node_Id); -- Verify that an operator has received some valid interpretation. If none -- was found, determine whether a use clause would make the operation -- legal. The variable Candidate_Type (defined in Sem_Type) is set for -- every type compatible with the operator, even if the operator for the -- type is not directly visible. The routine uses this type to emit a more -- informative message. function Has_Possible_User_Defined_Literal (N : Node_Id) return Boolean; -- Ada 2022: if an operand is a literal, it may be subject to an -- implicit conversion to a type for which a user-defined literal -- function exists. During the first pass of type resolution we do -- not know the context imposed on the literal, so we assume that -- the literal type is a valid candidate and rely on the second pass -- of resolution to find the type with the proper aspect. We only -- add this interpretation if no other one was found, which may be -- too restrictive but seems sufficient to handle most proper uses -- of the new aspect. It is unclear whether a full implementation of -- these aspects can be achieved without larger modifications to the -- two-pass resolution algorithm. function Is_Effectively_Visible_Operator (N : Node_Id; Typ : Entity_Id) return Boolean is (Is_Visible_Operator (N => N, Typ => Typ) or else -- test for a rewritten Foo."+" call (N /= Original_Node (N) and then Is_Effectively_Visible_Operator (N => Original_Node (N), Typ => Typ)) or else Checking_Potentially_Static_Expression or else not Comes_From_Source (N)); -- Return True iff either Is_Visible_Operator returns True or if -- there is a reason it is ok for Is_Visible_Operator to return False. function Possible_Type_For_Conditional_Expression (T1, T2 : Entity_Id) return Entity_Id; -- Given two types T1 and T2 that are _not_ compatible, return a type that -- may still be used as the possible type of a conditional expression whose -- dependent expressions, or part thereof, have type T1 and T2 respectively -- during the first phase of type resolution, or Empty if such a type does -- not exist. -- The typical example is an if_expression whose then_expression is of a -- tagged type and whose else_expresssion is of an extension of this type: -- the types are not compatible but such an if_expression can be legal if -- its expected type is the 'Class of the tagged type, so the function will -- return the tagged type in this case. If the expected type turns out to -- be something else, including the tagged type itself, then an error will -- be given during the second phase of type resolution. procedure Remove_Abstract_Operations (N : Node_Id); -- Ada 2005: implementation of AI-310. An abstract non-dispatching -- operation is not a candidate interpretation. function Try_Container_Indexing (N : Node_Id; Prefix : Node_Id; Exprs : List_Id) return Boolean; -- AI05-0139: Generalized indexing to support iterators over containers -- ??? Need to provide a more detailed spec of what this function does function Try_Indexed_Call (N : Node_Id; Nam : Entity_Id; Typ : Entity_Id; Skip_First : Boolean) return Boolean; -- If a function has defaults for all its actuals, a call to it may in fact -- be an indexing on the result of the call. Try_Indexed_Call attempts the -- interpretation as an indexing, prior to analysis as a call. If both are -- possible, the node is overloaded with both interpretations (same symbol -- but two different types). If the call is written in prefix form, the -- prefix becomes the first parameter in the call, and only the remaining -- actuals must be checked for the presence of defaults. function Try_Indirect_Call (N : Node_Id; Nam : Entity_Id; Typ : Entity_Id) return Boolean; -- Similarly, a function F that needs no actuals can return an access to a -- subprogram, and the call F (X) interpreted as F.all (X). In this case -- the call may be overloaded with both interpretations. procedure wpo (T : Entity_Id); pragma Warnings (Off, wpo); -- Used for debugging: obtain list of primitive operations even if -- type is not frozen and dispatch table is not built yet. ------------------------ -- Ambiguous_Operands -- ------------------------ procedure Ambiguous_Operands (N : Node_Id) is procedure List_Operand_Interps (Opnd : Node_Id); -------------------------- -- List_Operand_Interps -- -------------------------- procedure List_Operand_Interps (Opnd : Node_Id) is Nam : Node_Id := Empty; Err : Node_Id := N; begin if Is_Overloaded (Opnd) then if Nkind (Opnd) in N_Op then Nam := Opnd; elsif Nkind (Opnd) = N_Function_Call then Nam := Name (Opnd); elsif Ada_Version >= Ada_2012 then declare It : Interp; I : Interp_Index; begin Get_First_Interp (Opnd, I, It); while Present (It.Nam) loop if Has_Implicit_Dereference (It.Typ) then Error_Msg_N ("can be interpreted as implicit dereference", Opnd); return; end if; Get_Next_Interp (I, It); end loop; end; return; end if; else return; end if; if Opnd = Left_Opnd (N) then Error_Msg_N ("\left operand has the following interpretations", N); else Error_Msg_N ("\right operand has the following interpretations", N); Err := Opnd; end if; List_Interps (Nam, Err); end List_Operand_Interps; -- Start of processing for Ambiguous_Operands begin if Nkind (N) in N_Membership_Test then Error_Msg_N ("ambiguous operands for membership", N); elsif Nkind (N) in N_Op_Eq | N_Op_Ne then Error_Msg_N ("ambiguous operands for equality", N); else Error_Msg_N ("ambiguous operands for comparison", N); end if; if All_Errors_Mode then List_Operand_Interps (Left_Opnd (N)); List_Operand_Interps (Right_Opnd (N)); else Error_Msg_N ("\use -gnatf switch for details", N); end if; end Ambiguous_Operands; ----------------------- -- Analyze_Aggregate -- ----------------------- -- Most of the analysis of Aggregates requires that the type be known, and -- is therefore put off until resolution of the context. Delta aggregates -- have a base component that determines the enclosing aggregate type so -- its type can be ascertained earlier. This also allows delta aggregates -- to appear in the context of a record type with a private extension, as -- per the latest update of AI12-0127. procedure Analyze_Aggregate (N : Node_Id) is begin if No (Etype (N)) then if Nkind (N) = N_Delta_Aggregate then declare Base : constant Node_Id := Expression (N); I : Interp_Index; It : Interp; begin Analyze (Base); -- If the base is overloaded, propagate interpretations to the -- enclosing aggregate. if Is_Overloaded (Base) then Get_First_Interp (Base, I, It); Set_Etype (N, Any_Type); while Present (It.Nam) loop Add_One_Interp (N, It.Typ, It.Typ); Get_Next_Interp (I, It); end loop; else Set_Etype (N, Etype (Base)); end if; end; else Set_Etype (N, Any_Composite); end if; end if; end Analyze_Aggregate; ----------------------- -- Analyze_Allocator -- ----------------------- procedure Analyze_Allocator (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Sav_Errs : constant Nat := Serious_Errors_Detected; E : Node_Id := Expression (N); Acc_Type : Entity_Id; Type_Id : Entity_Id; P : Node_Id; C : Node_Id; Onode : Node_Id; begin -- Deal with allocator restrictions -- In accordance with H.4(7), the No_Allocators restriction only applies -- to user-written allocators. The same consideration applies to the -- No_Standard_Allocators_Before_Elaboration restriction. if Comes_From_Source (N) then Check_Restriction (No_Allocators, N); -- Processing for No_Standard_Allocators_After_Elaboration, loop to -- look at enclosing context, checking task/main subprogram case. C := N; P := Parent (C); while Present (P) loop -- For the task case we need a handled sequence of statements, -- where the occurrence of the allocator is within the statements -- and the parent is a task body if Nkind (P) = N_Handled_Sequence_Of_Statements and then Is_List_Member (C) and then List_Containing (C) = Statements (P) then Onode := Original_Node (Parent (P)); -- Check for allocator within task body, this is a definite -- violation of No_Allocators_After_Elaboration we can detect -- at compile time. if Nkind (Onode) = N_Task_Body then Check_Restriction (No_Standard_Allocators_After_Elaboration, N); exit; end if; end if; -- The other case is appearance in a subprogram body. This is -- a violation if this is a library level subprogram with no -- parameters. Note that this is now a static error even if the -- subprogram is not the main program (this is a change, in an -- earlier version only the main program was affected, and the -- check had to be done in the binder). if Nkind (P) = N_Subprogram_Body and then Nkind (Parent (P)) = N_Compilation_Unit and then No (Parameter_Specifications (Specification (P))) then Check_Restriction (No_Standard_Allocators_After_Elaboration, N); end if; C := P; P := Parent (C); end loop; end if; -- Ada 2012 (AI05-0111-3): Analyze the subpool_specification, if -- any. The expected type for the name is any type. A non-overloading -- rule then requires it to be of a type descended from -- System.Storage_Pools.Subpools.Subpool_Handle. -- This isn't exactly what the AI says, but it seems to be the right -- rule. The AI should be fixed.??? declare Subpool : constant Node_Id := Subpool_Handle_Name (N); begin if Present (Subpool) then Analyze (Subpool); if Is_Overloaded (Subpool) then Error_Msg_N ("ambiguous subpool handle", Subpool); end if; -- Check that Etype (Subpool) is descended from Subpool_Handle Resolve (Subpool); end if; end; -- Analyze the qualified expression or subtype indication if Nkind (E) = N_Qualified_Expression then Acc_Type := Create_Itype (E_Allocator_Type, N); Set_Etype (Acc_Type, Acc_Type); Find_Type (Subtype_Mark (E)); -- Analyze the qualified expression, and apply the name resolution -- rule given in 4.7(3). Analyze (E); Type_Id := Etype (E); Set_Directly_Designated_Type (Acc_Type, Type_Id); -- A qualified expression requires an exact match of the type, -- class-wide matching is not allowed. -- if Is_Class_Wide_Type (Type_Id) -- and then Base_Type -- (Etype (Expression (E))) /= Base_Type (Type_Id) -- then -- Wrong_Type (Expression (E), Type_Id); -- end if; -- We don't analyze the qualified expression itself because it's -- part of the allocator. It is fully analyzed and resolved when -- the allocator is resolved with the context type. Set_Etype (E, Type_Id); -- Case where allocator has a subtype indication else -- If the allocator includes a N_Subtype_Indication then a -- constraint is present, otherwise the node is a subtype mark. -- Introduce an explicit subtype declaration into the tree -- defining some anonymous subtype and rewrite the allocator to -- use this subtype rather than the subtype indication. -- It is important to introduce the explicit subtype declaration -- so that the bounds of the subtype indication are attached to -- the tree in case the allocator is inside a generic unit. -- Finally, if there is no subtype indication and the type is -- a tagged unconstrained type with discriminants, the designated -- object is constrained by their default values, and it is -- simplest to introduce an explicit constraint now. In some cases -- this is done during expansion, but freeze actions are certain -- to be emitted in the proper order if constraint is explicit. if Is_Entity_Name (E) and then Expander_Active then Find_Type (E); Type_Id := Entity (E); if Is_Tagged_Type (Type_Id) and then Has_Defaulted_Discriminants (Type_Id) and then not Is_Constrained (Type_Id) then declare Constr : constant List_Id := New_List; Loc : constant Source_Ptr := Sloc (E); Discr : Entity_Id := First_Discriminant (Type_Id); begin while Present (Discr) loop Append (Discriminant_Default_Value (Discr), Constr); Next_Discriminant (Discr); end loop; Rewrite (E, Make_Subtype_Indication (Loc, Subtype_Mark => New_Occurrence_Of (Type_Id, Loc), Constraint => Make_Index_Or_Discriminant_Constraint (Loc, Constraints => Constr))); end; -- Rewrite the mutably tagged type to a non-class-wide type for -- proper initialization. elsif Is_Mutably_Tagged_Type (Type_Id) then Rewrite (E, New_Occurrence_Of (Etype (Type_Id), Loc)); end if; end if; if Nkind (E) = N_Subtype_Indication then declare Def_Id : Entity_Id; Base_Typ : Entity_Id; begin -- A constraint is only allowed for a composite type in Ada -- 95. In Ada 83, a constraint is also allowed for an -- access-to-composite type, but the constraint is ignored. Find_Type (Subtype_Mark (E)); Base_Typ := Entity (Subtype_Mark (E)); if Is_Elementary_Type (Base_Typ) then if not (Ada_Version = Ada_83 and then Is_Access_Type (Base_Typ)) then Error_Msg_N ("constraint not allowed here", E); if Nkind (Constraint (E)) = N_Index_Or_Discriminant_Constraint then Error_Msg_N -- CODEFIX ("\if qualified expression was meant, " & "use apostrophe", Constraint (E)); end if; end if; -- Get rid of the bogus constraint: Rewrite (E, New_Copy_Tree (Subtype_Mark (E))); Analyze_Allocator (N); return; end if; -- In GNATprove mode we need to preserve the link between -- the original subtype indication and the anonymous subtype, -- to extend proofs to constrained access types. We only do -- that outside of spec expressions, otherwise the declaration -- cannot be inserted and analyzed. In such a case, GNATprove -- later rejects the allocator as it is not used here in -- a non-interfering context (SPARK 4.8(2) and 7.1.3(10)). if Expander_Active or else (GNATprove_Mode and then not In_Spec_Expression) then Def_Id := Make_Temporary (Loc, 'S'); declare Subtype_Decl : constant Node_Id := Make_Subtype_Declaration (Loc, Defining_Identifier => Def_Id, Subtype_Indication => Relocate_Node (E)); begin Insert_Action (E, Subtype_Decl); -- Handle unusual case where Insert_Action does not -- analyze the declaration. Subtype_Decl must be -- preanalyzed before call to Process_Subtype below. Preanalyze (Subtype_Decl); end; if Sav_Errs /= Serious_Errors_Detected and then Nkind (Constraint (E)) = N_Index_Or_Discriminant_Constraint then Error_Msg_N -- CODEFIX ("if qualified expression was meant, use apostrophe!", Constraint (E)); end if; E := New_Occurrence_Of (Def_Id, Loc); Rewrite (Expression (N), E); end if; end; end if; Type_Id := Process_Subtype (E, N); Acc_Type := Create_Itype (E_Allocator_Type, N); Set_Etype (Acc_Type, Acc_Type); Set_Directly_Designated_Type (Acc_Type, Type_Id); Check_Fully_Declared (Type_Id, N); -- Ada 2005 (AI-231): If the designated type is itself an access -- type that excludes null, its default initialization will -- be a null object, and we can insert an unconditional raise -- before the allocator. -- Ada 2012 (AI-104): A not null indication here is altogether -- illegal. if Can_Never_Be_Null (Type_Id) then if Expander_Active then Apply_Compile_Time_Constraint_Error (N, "null value not allowed here??", CE_Null_Not_Allowed); elsif Warn_On_Ada_2012_Compatibility then Error_Msg_N ("null value not allowed here in Ada 2012?y?", E); end if; end if; -- Check for missing initialization. Skip this check if the allocator -- is made for a special return object or if we already had errors on -- analyzing the allocator since, in that case, these are very likely -- cascaded errors. if not Is_Definite_Subtype (Type_Id) and then not For_Special_Return_Object (N) and then Serious_Errors_Detected = Sav_Errs then if Is_Class_Wide_Type (Type_Id) then Error_Msg_N ("initialization required in class-wide allocation", N); else if Ada_Version < Ada_2005 and then Is_Limited_Type (Type_Id) then Error_Msg_N ("unconstrained allocation not allowed", N); if Is_Array_Type (Type_Id) then Error_Msg_N ("\constraint with array bounds required", N); elsif Has_Unknown_Discriminants (Type_Id) then null; else pragma Assert (Has_Discriminants (Type_Id)); Error_Msg_N ("\constraint with discriminant values required", N); end if; -- Limited Ada 2005 and general nonlimited case. -- This is an error, except in the case of an -- uninitialized allocator that is generated -- for a build-in-place function return of a -- discriminated but compile-time-known-size -- type. else if Is_Rewrite_Substitution (N) and then Nkind (Original_Node (N)) = N_Allocator then declare Qual : constant Node_Id := Expression (Original_Node (N)); pragma Assert (Nkind (Qual) = N_Qualified_Expression); Call : constant Node_Id := Expression (Qual); pragma Assert (Is_Expanded_Build_In_Place_Call (Call)); begin null; end; else Error_Msg_N ("uninitialized unconstrained allocation not " & "allowed", N); if Is_Array_Type (Type_Id) then Error_Msg_N ("\qualified expression or constraint with " & "array bounds required", N); elsif Has_Unknown_Discriminants (Type_Id) then Error_Msg_N ("\qualified expression required", N); else pragma Assert (Has_Discriminants (Type_Id)); Error_Msg_N ("\qualified expression or constraint with " & "discriminant values required", N); end if; end if; end if; end if; end if; end if; if Is_Abstract_Type (Type_Id) then Error_Msg_N ("cannot allocate abstract object", E); end if; Set_Etype (N, Acc_Type); -- If this is an allocator for the return stack, then no restriction may -- be violated since it's just a low-level access to the primary stack. if Nkind (Parent (N)) = N_Object_Declaration and then Is_Entity_Name (Object_Definition (Parent (N))) and then Is_Access_Type (Entity (Object_Definition (Parent (N)))) then declare Pool : constant Entity_Id := Associated_Storage_Pool (Root_Type (Entity (Object_Definition (Parent (N))))); begin if Present (Pool) and then Is_RTE (Pool, RE_RS_Pool) then goto Leave; end if; end; end if; if Has_Task (Designated_Type (Acc_Type)) then Check_Restriction (No_Tasking, N); Check_Restriction (Max_Tasks, N); Check_Restriction (No_Task_Allocators, N); end if; -- Check restriction against dynamically allocated protected objects if Has_Protected (Designated_Type (Acc_Type)) then Check_Restriction (No_Protected_Type_Allocators, N); end if; -- AI05-0013-1: No_Nested_Finalization forbids allocators if the access -- type is nested, and the designated type needs finalization. The rule -- is conservative in that class-wide types need finalization. if Needs_Finalization (Designated_Type (Acc_Type)) and then not Is_Library_Level_Entity (Acc_Type) then Check_Restriction (No_Nested_Finalization, N); end if; -- Check that an allocator of a nested access type doesn't create a -- protected object when restriction No_Local_Protected_Objects applies. if Has_Protected (Designated_Type (Acc_Type)) and then not Is_Library_Level_Entity (Acc_Type) then Check_Restriction (No_Local_Protected_Objects, N); end if; -- Likewise for No_Local_Timing_Events if Has_Timing_Event (Designated_Type (Acc_Type)) and then not Is_Library_Level_Entity (Acc_Type) then Check_Restriction (No_Local_Timing_Events, N); end if; -- If the No_Streams restriction is set, check that the type of the -- object is not, and does not contain, any subtype derived from -- Ada.Streams.Root_Stream_Type. Note that we guard the call to -- Has_Stream just for efficiency reasons. There is no point in -- spending time on a Has_Stream check if the restriction is not set. if Restriction_Check_Required (No_Streams) then if Has_Stream (Designated_Type (Acc_Type)) then Check_Restriction (No_Streams, N); end if; end if; if not Is_Library_Level_Entity (Acc_Type) then Check_Restriction (No_Local_Allocators, N); end if; <> if Serious_Errors_Detected > Sav_Errs then Set_Error_Posted (N); Set_Etype (N, Any_Type); end if; end Analyze_Allocator; --------------------------- -- Analyze_Arithmetic_Op -- --------------------------- procedure Analyze_Arithmetic_Op (N : Node_Id) is L : constant Node_Id := Left_Opnd (N); R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id; begin Set_Etype (N, Any_Type); Candidate_Type := Empty; Analyze_Expression (L); Analyze_Expression (R); -- If the entity is already set, the node is the instantiation of a -- generic node with a non-local reference, or was manufactured by a -- call to Make_Op_xxx. In either case the entity is known to be valid, -- and we do not need to collect interpretations, instead we just get -- the single possible interpretation. if Present (Entity (N)) then Op_Id := Entity (N); if Ekind (Op_Id) = E_Operator then Find_Arithmetic_Types (L, R, Op_Id, N); else Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; -- Entity is not already set, so we do need to collect interpretations else Op_Id := Get_Name_Entity_Id (Chars (N)); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator and then Present (Next_Entity (First_Entity (Op_Id))) then Find_Arithmetic_Types (L, R, Op_Id, N); -- The following may seem superfluous, because an operator cannot -- be generic, but this ignores the cleverness of the author of -- ACVC bc1013a. elsif Is_Overloadable (Op_Id) then Analyze_User_Defined_Binary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; end if; Operator_Check (N); Check_Function_Writable_Actuals (N); end Analyze_Arithmetic_Op; ------------------ -- Analyze_Call -- ------------------ -- Function, procedure, and entry calls are checked here. The Name in -- the call may be overloaded. The actuals have been analyzed and may -- themselves be overloaded. On exit from this procedure, the node N -- may have zero, one or more interpretations. In the first case an -- error message is produced. In the last case, the node is flagged -- as overloaded and the interpretations are collected in All_Interp. -- If the name is an Access_To_Subprogram, it cannot be overloaded, but -- the type-checking is similar to that of other calls. procedure Analyze_Call (N : Node_Id) is Actuals : constant List_Id := Parameter_Associations (N); Loc : constant Source_Ptr := Sloc (N); Nam : Node_Id; X : Interp_Index; It : Interp; Nam_Ent : Entity_Id := Empty; Success : Boolean := False; Deref : Boolean := False; -- Flag indicates whether an interpretation of the prefix is a -- parameterless call that returns an access_to_subprogram. procedure Check_Writable_Actuals (N : Node_Id); -- If the call has out or in-out parameters then mark its outermost -- enclosing construct as a node on which the writable actuals check -- must be performed. function Name_Denotes_Function return Boolean; -- If the type of the name is an access to subprogram, this may be the -- type of a name, or the return type of the function being called. If -- the name is not an entity then it can denote a protected function. -- Until we distinguish Etype from Return_Type, we must use this routine -- to resolve the meaning of the name in the call. procedure No_Interpretation; -- Output error message when no valid interpretation exists ---------------------------- -- Check_Writable_Actuals -- ---------------------------- -- The identification of conflicts in calls to functions with writable -- actuals is performed in the analysis phase of the front end to ensure -- that it reports exactly the same errors compiling with and without -- expansion enabled. It is performed in two stages: -- 1) When a call to a function with out-mode parameters is found, -- we climb to the outermost enclosing construct that can be -- evaluated in arbitrary order and we mark it with the flag -- Check_Actuals. -- 2) When the analysis of the marked node is complete, we traverse -- its decorated subtree searching for conflicts (see function -- Sem_Util.Check_Function_Writable_Actuals). -- The unique exception to this general rule is for aggregates, since -- their analysis is performed by the front end in the resolution -- phase. For aggregates we do not climb to their enclosing construct: -- we restrict the analysis to the subexpressions initializing the -- aggregate components. -- This implies that the analysis of expressions containing aggregates -- is not complete, since there may be conflicts on writable actuals -- involving subexpressions of the enclosing logical or arithmetic -- expressions. However, we cannot wait and perform the analysis when -- the whole subtree is resolved, since the subtrees may be transformed, -- thus adding extra complexity and computation cost to identify and -- report exactly the same errors compiling with and without expansion -- enabled. procedure Check_Writable_Actuals (N : Node_Id) is begin if Comes_From_Source (N) and then Present (Get_Subprogram_Entity (N)) and then Has_Out_Or_In_Out_Parameter (Get_Subprogram_Entity (N)) then -- For procedures and entries there is no need to climb since -- we only need to check if the actuals of this call invoke -- functions whose out-mode parameters overlap. if Nkind (N) /= N_Function_Call then Set_Check_Actuals (N); -- For calls to functions we climb to the outermost enclosing -- construct where the out-mode actuals of this function may -- introduce conflicts. else declare Outermost : Node_Id := Empty; -- init to avoid warning P : Node_Id := N; begin while Present (P) loop -- For object declarations we can climb to the node from -- its object definition branch or from its initializing -- expression. We prefer to mark the child node as the -- outermost construct to avoid adding further complexity -- to the routine that will later take care of -- performing the writable actuals check. if Has_Arbitrary_Evaluation_Order (Nkind (P)) and then Nkind (P) not in N_Assignment_Statement | N_Object_Declaration then Outermost := P; end if; -- Avoid climbing more than needed exit when Stop_Subtree_Climbing (Nkind (P)) or else (Nkind (P) = N_Range and then Nkind (Parent (P)) not in N_In | N_Not_In); P := Parent (P); end loop; Set_Check_Actuals (Outermost); end; end if; end if; end Check_Writable_Actuals; --------------------------- -- Name_Denotes_Function -- --------------------------- function Name_Denotes_Function return Boolean is begin if Is_Entity_Name (Nam) then return Ekind (Entity (Nam)) = E_Function; elsif Nkind (Nam) = N_Selected_Component then return Ekind (Entity (Selector_Name (Nam))) = E_Function; else return False; end if; end Name_Denotes_Function; ----------------------- -- No_Interpretation -- ----------------------- procedure No_Interpretation is L : constant Boolean := Is_List_Member (N); K : constant Node_Kind := Nkind (Parent (N)); begin -- If the node is in a list whose parent is not an expression then it -- must be an attempted procedure call. if L and then K not in N_Subexpr then if Ekind (Entity (Nam)) = E_Generic_Procedure then Error_Msg_NE ("must instantiate generic procedure& before call", Nam, Entity (Nam)); else Error_Msg_N ("procedure or entry name expected", Nam); end if; -- Check for tasking cases where only an entry call will do elsif not L and then K in N_Entry_Call_Alternative | N_Triggering_Alternative then Error_Msg_N ("entry name expected", Nam); -- Otherwise give general error message else Error_Msg_N ("invalid prefix in call", Nam); end if; end No_Interpretation; -- Start of processing for Analyze_Call begin -- Initialize the type of the result of the call to the error type, -- which will be reset if the type is successfully resolved. Set_Etype (N, Any_Type); Nam := Name (N); if not Is_Overloaded (Nam) then -- Only one interpretation to check if Ekind (Etype (Nam)) = E_Subprogram_Type then Nam_Ent := Etype (Nam); -- If the prefix is an access_to_subprogram, this may be an indirect -- call. This is the case if the name in the call is not an entity -- name, or if it is a function name in the context of a procedure -- call. In this latter case, we have a call to a parameterless -- function that returns a pointer_to_procedure which is the entity -- being called. Finally, F (X) may be a call to a parameterless -- function that returns a pointer to a function with parameters. -- Note that if F returns an access-to-subprogram whose designated -- type is an array, F (X) cannot be interpreted as an indirect call -- through the result of the call to F. elsif Is_Access_Subprogram_Type (Base_Type (Etype (Nam))) and then (not Name_Denotes_Function or else Nkind (N) = N_Procedure_Call_Statement or else (Nkind (Parent (N)) /= N_Explicit_Dereference and then Is_Entity_Name (Nam) and then No (First_Formal (Entity (Nam))) and then not Is_Array_Type (Etype (Designated_Type (Etype (Nam)))) and then Present (Actuals))) then Nam_Ent := Designated_Type (Etype (Nam)); Insert_Explicit_Dereference (Nam); -- Selected component case. Simple entry or protected operation, -- where the entry name is given by the selector name. elsif Nkind (Nam) = N_Selected_Component then Nam_Ent := Entity (Selector_Name (Nam)); if Ekind (Nam_Ent) not in E_Entry | E_Entry_Family | E_Function | E_Procedure then Error_Msg_N ("name in call is not a callable entity", Nam); Set_Etype (N, Any_Type); return; end if; -- If the name is an Indexed component, it can be a call to a member -- of an entry family. The prefix must be a selected component whose -- selector is the entry. Analyze_Procedure_Call normalizes several -- kinds of call into this form. elsif Nkind (Nam) = N_Indexed_Component then if Nkind (Prefix (Nam)) = N_Selected_Component then Nam_Ent := Entity (Selector_Name (Prefix (Nam))); else Error_Msg_N ("name in call is not a callable entity", Nam); Set_Etype (N, Any_Type); return; end if; elsif not Is_Entity_Name (Nam) then Error_Msg_N ("name in call is not a callable entity", Nam); Set_Etype (N, Any_Type); return; else Nam_Ent := Entity (Nam); -- If not overloadable, this may be a generalized indexing -- operation with named associations. Rewrite again as an -- indexed component and analyze as container indexing. if not Is_Overloadable (Nam_Ent) then if Present (Find_Value_Of_Aspect (Etype (Nam_Ent), Aspect_Constant_Indexing)) then Replace (N, Make_Indexed_Component (Sloc (N), Prefix => Nam, Expressions => Parameter_Associations (N))); if Try_Container_Indexing (N, Nam, Expressions (N)) then return; else No_Interpretation; end if; else No_Interpretation; end if; return; end if; end if; -- Operations generated for RACW stub types are called only through -- dispatching, and can never be the static interpretation of a call. if Is_RACW_Stub_Type_Operation (Nam_Ent) then No_Interpretation; return; end if; Analyze_One_Call (N, Nam_Ent, True, Success); -- If the nonoverloaded interpretation is a call to an abstract -- nondispatching operation, then flag an error and return. if Is_Overloadable (Nam_Ent) and then Is_Abstract_Subprogram (Nam_Ent) and then not Is_Dispatching_Operation (Nam_Ent) then Nondispatching_Call_To_Abstract_Operation (N, Nam_Ent); return; end if; -- If this is an indirect call, the return type of the access_to -- subprogram may be an incomplete type. At the point of the call, -- use the full type if available, and at the same time update the -- return type of the access_to_subprogram. if Success and then Nkind (Nam) = N_Explicit_Dereference and then Ekind (Etype (N)) = E_Incomplete_Type and then Present (Full_View (Etype (N))) then Set_Etype (N, Full_View (Etype (N))); Set_Etype (Nam_Ent, Etype (N)); end if; -- Overloaded call else -- An overloaded selected component must denote overloaded operations -- of a concurrent type. The interpretations are attached to the -- simple name of those operations. if Nkind (Nam) = N_Selected_Component then Nam := Selector_Name (Nam); end if; Get_First_Interp (Nam, X, It); while Present (It.Nam) loop Nam_Ent := It.Nam; Deref := False; -- Name may be call that returns an access to subprogram, or more -- generally an overloaded expression one of whose interpretations -- yields an access to subprogram. If the name is an entity, we do -- not dereference, because the node is a call that returns the -- access type: note difference between f(x), where the call may -- return an access subprogram type, and f(x)(y), where the type -- returned by the call to f is implicitly dereferenced to analyze -- the outer call. if Is_Access_Type (Nam_Ent) then Nam_Ent := Designated_Type (Nam_Ent); elsif Is_Access_Type (Etype (Nam_Ent)) and then (not Is_Entity_Name (Nam) or else Nkind (N) = N_Procedure_Call_Statement) and then Ekind (Designated_Type (Etype (Nam_Ent))) = E_Subprogram_Type then Nam_Ent := Designated_Type (Etype (Nam_Ent)); if Is_Entity_Name (Nam) then Deref := True; end if; end if; -- If the call has been rewritten from a prefixed call, the first -- parameter has been analyzed, but may need a subsequent -- dereference, so skip its analysis now. if Is_Rewrite_Substitution (N) and then Nkind (Original_Node (N)) = Nkind (N) and then Nkind (Name (N)) /= Nkind (Name (Original_Node (N))) and then Present (Parameter_Associations (N)) and then Present (Etype (First (Parameter_Associations (N)))) then Analyze_One_Call (N, Nam_Ent, False, Success, Skip_First => True); else Analyze_One_Call (N, Nam_Ent, False, Success); end if; -- If the interpretation succeeds, mark the proper type of the -- prefix (any valid candidate will do). If not, remove the -- candidate interpretation. If this is a parameterless call -- on an anonymous access to subprogram, X is a variable with -- an access discriminant D, the entity in the interpretation is -- D, so rewrite X as X.D.all. if Success then if Deref and then Nkind (Parent (N)) /= N_Explicit_Dereference then if Ekind (It.Nam) = E_Discriminant and then Has_Implicit_Dereference (It.Nam) then Rewrite (Name (N), Make_Explicit_Dereference (Loc, Prefix => Make_Selected_Component (Loc, Prefix => New_Occurrence_Of (Entity (Nam), Loc), Selector_Name => New_Occurrence_Of (It.Nam, Loc)))); Analyze (N); return; else Set_Entity (Nam, It.Nam); Insert_Explicit_Dereference (Nam); Set_Etype (Nam, Nam_Ent); end if; else Set_Etype (Nam, It.Typ); end if; elsif Nkind (Name (N)) in N_Function_Call | N_Selected_Component then Remove_Interp (X); end if; Get_Next_Interp (X, It); end loop; -- If the name is the result of a function call, it can only be a -- call to a function returning an access to subprogram. Insert -- explicit dereference. if Nkind (Nam) = N_Function_Call then Insert_Explicit_Dereference (Nam); end if; if Etype (N) = Any_Type then -- None of the interpretations is compatible with the actuals Diagnose_Call (N, Nam); -- Special checks for uninstantiated put routines if Nkind (N) = N_Procedure_Call_Statement and then Is_Entity_Name (Nam) and then Chars (Nam) = Name_Put and then List_Length (Actuals) = 1 then declare Arg : constant Node_Id := First (Actuals); Typ : Entity_Id; begin if Nkind (Arg) = N_Parameter_Association then Typ := Etype (Explicit_Actual_Parameter (Arg)); else Typ := Etype (Arg); end if; if Is_Signed_Integer_Type (Typ) then Error_Msg_N ("possible missing instantiation of " & "'Text_'I'O.'Integer_'I'O!", Nam); elsif Is_Modular_Integer_Type (Typ) then Error_Msg_N ("possible missing instantiation of " & "'Text_'I'O.'Modular_'I'O!", Nam); elsif Is_Floating_Point_Type (Typ) then Error_Msg_N ("possible missing instantiation of " & "'Text_'I'O.'Float_'I'O!", Nam); elsif Is_Ordinary_Fixed_Point_Type (Typ) then Error_Msg_N ("possible missing instantiation of " & "'Text_'I'O.'Fixed_'I'O!", Nam); elsif Is_Decimal_Fixed_Point_Type (Typ) then Error_Msg_N ("possible missing instantiation of " & "'Text_'I'O.'Decimal_'I'O!", Nam); elsif Is_Enumeration_Type (Typ) then Error_Msg_N ("possible missing instantiation of " & "'Text_'I'O.'Enumeration_'I'O!", Nam); end if; end; end if; elsif not Is_Overloaded (N) and then Is_Entity_Name (Nam) then -- Resolution yields a single interpretation. Verify that the -- reference has capitalization consistent with the declaration. Set_Entity_With_Checks (Nam, Entity (Nam)); Generate_Reference (Entity (Nam), Nam); Set_Etype (Nam, Etype (Entity (Nam))); else Remove_Abstract_Operations (N); end if; end if; -- Check the accessibility level for actuals for explicitly aliased -- formals when a function call appears within a return statement. -- This is only checked if the enclosing subprogram Comes_From_Source, -- to avoid issuing errors on calls occurring in wrapper subprograms -- (for example, where the call is part of an expression of an aspect -- associated with a wrapper, such as Pre'Class). if Nkind (N) = N_Function_Call and then Comes_From_Source (N) and then Present (Nam_Ent) and then In_Return_Value (N) and then Comes_From_Source (Current_Subprogram) then declare Form : Node_Id; Act : Node_Id; begin Act := First_Actual (N); Form := First_Formal (Nam_Ent); while Present (Form) and then Present (Act) loop -- Check whether the formal is aliased and if the accessibility -- level of the actual is deeper than the accessibility level -- of the enclosing subprogram to which the current return -- statement applies. -- Should we be checking Is_Entity_Name on Act? Won't this miss -- other cases ??? if Is_Explicitly_Aliased (Form) and then Is_Entity_Name (Act) and then Static_Accessibility_Level (Act, Zero_On_Dynamic_Level) > Subprogram_Access_Level (Current_Subprogram) then Error_Msg_N ("actual for explicitly aliased formal is too" & " short lived", Act); end if; Next_Formal (Form); Next_Actual (Act); end loop; end; end if; if Ada_Version >= Ada_2012 then -- Check if the call contains a function with writable actuals Check_Writable_Actuals (N); -- If found and the outermost construct that can be evaluated in -- an arbitrary order is precisely this call, then check all its -- actuals. Check_Function_Writable_Actuals (N); -- The return type of the function may be incomplete. This can be -- the case if the type is a generic formal, or a limited view. It -- can also happen when the function declaration appears before the -- full view of the type (which is legal in Ada 2012) and the call -- appears in a different unit, in which case the incomplete view -- must be replaced with the full view (or the nonlimited view) -- to prevent subsequent type errors. Note that the usual install/ -- removal of limited_with clauses is not sufficient to handle this -- case, because the limited view may have been captured in another -- compilation unit that defines the current function. if Is_Incomplete_Type (Etype (N)) then if Present (Full_View (Etype (N))) then if Is_Entity_Name (Nam) then Set_Etype (Nam, Full_View (Etype (N))); Set_Etype (Entity (Nam), Full_View (Etype (N))); end if; Set_Etype (N, Full_View (Etype (N))); -- If the call is within a thunk, the nonlimited view should be -- analyzed eventually (see also Analyze_Return_Type). elsif From_Limited_With (Etype (N)) and then Present (Non_Limited_View (Etype (N))) and then (Ekind (Non_Limited_View (Etype (N))) /= E_Incomplete_Type or else Is_Thunk (Current_Scope)) then Set_Etype (N, Non_Limited_View (Etype (N))); -- If there is no completion for the type, this may be because -- there is only a limited view of it and there is nothing in -- the context of the current unit that has required a regular -- compilation of the unit containing the type. We recognize -- this unusual case by the fact that unit is not analyzed. -- Note that the call being analyzed is in a different unit from -- the function declaration, and nothing indicates that the type -- is a limited view. elsif Ekind (Scope (Etype (N))) = E_Package and then Present (Limited_View (Scope (Etype (N)))) and then not Analyzed (Unit_Declaration_Node (Scope (Etype (N)))) then Error_Msg_NE ("cannot call function that returns limited view of}", N, Etype (N)); Error_Msg_NE ("\there must be a regular with_clause for package & in the " & "current unit, or in some unit in its context", N, Scope (Etype (N))); Set_Etype (N, Any_Type); end if; end if; end if; end Analyze_Call; ----------------------------- -- Analyze_Case_Expression -- ----------------------------- procedure Analyze_Case_Expression (N : Node_Id) is Expr : constant Node_Id := Expression (N); First_Alt : constant Node_Id := First (Alternatives (N)); First_Expr : Node_Id := Empty; -- First expression in the case where there is some type information -- available, i.e. there is not Any_Type everywhere, which can happen -- because of some error. Second_Expr : Node_Id := Empty; -- Second expression as above Wrong_Alt : Node_Id := Empty; -- For error reporting procedure Non_Static_Choice_Error (Choice : Node_Id); -- Error routine invoked by the generic instantiation below when -- the case expression has a non static choice. procedure Check_Next_Expression (T : Entity_Id; Alt : Node_Id); -- Check one interpretation of the next expression with type T procedure Check_Expression_Pair (T1, T2 : Entity_Id; Alt : Node_Id); -- Check first expression with type T1 and next expression with type T2 package Case_Choices_Analysis is new Generic_Analyze_Choices (Process_Associated_Node => No_OP); use Case_Choices_Analysis; package Case_Choices_Checking is new Generic_Check_Choices (Process_Empty_Choice => No_OP, Process_Non_Static_Choice => Non_Static_Choice_Error, Process_Associated_Node => No_OP); use Case_Choices_Checking; ----------------------------- -- Non_Static_Choice_Error -- ----------------------------- procedure Non_Static_Choice_Error (Choice : Node_Id) is begin Flag_Non_Static_Expr ("choice given in case expression is not static!", Choice); end Non_Static_Choice_Error; --------------------------- -- Check_Next_Expression -- --------------------------- procedure Check_Next_Expression (T : Entity_Id; Alt : Node_Id) is Next_Expr : constant Node_Id := Expression (Alt); I : Interp_Index; It : Interp; begin if Next_Expr = First_Expr then Check_Next_Expression (T, Next (Alt)); return; end if; -- Loop through the interpretations of the next expression if not Is_Overloaded (Next_Expr) then Check_Expression_Pair (T, Etype (Next_Expr), Alt); else Get_First_Interp (Next_Expr, I, It); while Present (It.Typ) loop Check_Expression_Pair (T, It.Typ, Alt); Get_Next_Interp (I, It); end loop; end if; end Check_Next_Expression; --------------------------- -- Check_Expression_Pair -- --------------------------- procedure Check_Expression_Pair (T1, T2 : Entity_Id; Alt : Node_Id) is Next_Expr : constant Node_Id := Expression (Alt); T : Entity_Id; begin if Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1) then T := Specific_Type (T1, T2); elsif Is_User_Defined_Literal (First_Expr, T2) then T := T2; elsif Is_User_Defined_Literal (Next_Expr, T1) then T := T1; else T := Possible_Type_For_Conditional_Expression (T1, T2); if No (T) then Wrong_Alt := Alt; return; end if; end if; if Present (Next (Alt)) then Check_Next_Expression (T, Next (Alt)); else Add_One_Interp (N, T, T); end if; end Check_Expression_Pair; -- Local variables Alt : Node_Id; Exp_Type : Entity_Id; Exp_Btype : Entity_Id; I : Interp_Index; It : Interp; Others_Present : Boolean; -- Start of processing for Analyze_Case_Expression begin Analyze_And_Resolve (Expr, Any_Discrete); Check_Unset_Reference (Expr); Exp_Type := Etype (Expr); Exp_Btype := Base_Type (Exp_Type); Set_Etype (N, Any_Type); Alt := First_Alt; while Present (Alt) loop if Error_Posted (Expression (Alt)) then return; end if; Analyze_Expression (Expression (Alt)); if Etype (Expression (Alt)) /= Any_Type then if No (First_Expr) then First_Expr := Expression (Alt); elsif No (Second_Expr) then Second_Expr := Expression (Alt); end if; end if; Next (Alt); end loop; -- Get our initial type from the first expression for which we got some -- useful type information from the expression. if No (First_Expr) then return; end if; -- The expression must be of a discrete type which must be determinable -- independently of the context in which the expression occurs, but -- using the fact that the expression must be of a discrete type. -- Moreover, the type this expression must not be a character literal -- (which is always ambiguous). -- If error already reported by Resolve, nothing more to do if Exp_Btype = Any_Discrete or else Exp_Btype = Any_Type then return; -- Special case message for character literal elsif Exp_Btype = Any_Character then Error_Msg_N ("character literal as case expression is ambiguous", Expr); return; end if; -- If the case expression is a formal object of mode in out, then -- treat it as having a nonstatic subtype by forcing use of the base -- type (which has to get passed to Check_Case_Choices below). Also -- use base type when the case expression is parenthesized. if Paren_Count (Expr) > 0 or else (Is_Entity_Name (Expr) and then Ekind (Entity (Expr)) = E_Generic_In_Out_Parameter) then Exp_Type := Exp_Btype; end if; -- The case expression alternatives cover the range of a static subtype -- subject to aspect Static_Predicate. Do not check the choices when the -- case expression has not been fully analyzed yet because this may lead -- to bogus errors. if Is_OK_Static_Subtype (Exp_Type) and then Has_Static_Predicate_Aspect (Exp_Type) and then In_Spec_Expression then null; -- Call Analyze_Choices and Check_Choices to do the rest of the work else Analyze_Choices (Alternatives (N), Exp_Type); Check_Choices (N, Alternatives (N), Exp_Type, Others_Present); if Exp_Type = Universal_Integer and then not Others_Present then Error_Msg_N ("case on universal integer requires OTHERS choice", Expr); return; end if; end if; -- RM 4.5.7(10/3): If the case_expression is the operand of a type -- conversion, the type of the case_expression is the target type -- of the conversion. if Nkind (Parent (N)) = N_Type_Conversion then Set_Etype (N, Etype (Parent (N))); return; end if; -- Loop through the interpretations of the first expression and check -- the other expressions if present. if not Is_Overloaded (First_Expr) then if Present (Second_Expr) then Check_Next_Expression (Etype (First_Expr), First_Alt); else Set_Etype (N, Etype (First_Expr)); end if; else Get_First_Interp (First_Expr, I, It); while Present (It.Typ) loop if Present (Second_Expr) then Check_Next_Expression (It.Typ, First_Alt); else Add_One_Interp (N, It.Typ, It.Typ); end if; Get_Next_Interp (I, It); end loop; end if; -- If no possible interpretation has been found, the type of the wrong -- alternative doesn't match any interpretation of the FIRST expression. if Etype (N) = Any_Type and then Present (Wrong_Alt) then Second_Expr := Expression (Wrong_Alt); if Is_Overloaded (First_Expr) then if Is_Overloaded (Second_Expr) then Error_Msg_N ("no interpretation compatible with those of previous " & "alternative", Second_Expr); else Error_Msg_N ("type incompatible with interpretations of previous " & "alternative", Second_Expr); Error_Msg_NE ("\this alternative has}!", Second_Expr, Etype (Second_Expr)); end if; else if Is_Overloaded (Second_Expr) then Error_Msg_N ("no interpretation compatible with type of previous " & "alternative", Second_Expr); Error_Msg_NE ("\previous alternative has}!", Second_Expr, Etype (First_Expr)); else Error_Msg_N ("type incompatible with that of previous alternative", Second_Expr); Error_Msg_NE ("\previous alternative has}!", Second_Expr, Etype (First_Expr)); Error_Msg_NE ("\this alternative has}!", Second_Expr, Etype (Second_Expr)); end if; end if; end if; end Analyze_Case_Expression; --------------------------- -- Analyze_Concatenation -- --------------------------- procedure Analyze_Concatenation (N : Node_Id) is -- We wish to avoid deep recursion, because concatenations are often -- deeply nested, as in A&B&...&Z. Therefore, we walk down the left -- operands nonrecursively until we find something that is not a -- concatenation (A in this case), or has already been analyzed. We -- analyze that, and then walk back up the tree following Parent -- pointers, calling Analyze_Concatenation_Rest to do the rest of the -- work at each level. The Parent pointers allow us to avoid recursion, -- and thus avoid running out of memory. NN : Node_Id := N; L : Node_Id; begin Candidate_Type := Empty; -- The following code is equivalent to: -- Set_Etype (N, Any_Type); -- Analyze_Expression (Left_Opnd (N)); -- Analyze_Concatenation_Rest (N); -- where the Analyze_Expression call recurses back here if the left -- operand is a concatenation. -- Walk down left operands loop Set_Etype (NN, Any_Type); L := Left_Opnd (NN); exit when Nkind (L) /= N_Op_Concat or else Analyzed (L); NN := L; end loop; -- Now (given the above example) NN is A&B and L is A -- First analyze L ... Analyze_Expression (L); -- ... then walk NN back up until we reach N (where we started), calling -- Analyze_Concatenation_Rest along the way. loop Analyze_Concatenation_Rest (NN); exit when NN = N; NN := Parent (NN); end loop; end Analyze_Concatenation; -------------------------------- -- Analyze_Concatenation_Rest -- -------------------------------- -- If the only one-dimensional array type in scope is String, -- this is the resulting type of the operation. Otherwise there -- will be a concatenation operation defined for each user-defined -- one-dimensional array. procedure Analyze_Concatenation_Rest (N : Node_Id) is L : constant Node_Id := Left_Opnd (N); R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id := Entity (N); LT : Entity_Id; RT : Entity_Id; begin Analyze_Expression (R); -- If the entity is present, the node appears in an instance, and -- denotes a predefined concatenation operation. The resulting type is -- obtained from the arguments when possible. If the arguments are -- aggregates, the array type and the concatenation type must be -- visible. if Present (Op_Id) then if Ekind (Op_Id) = E_Operator then LT := Base_Type (Etype (L)); RT := Base_Type (Etype (R)); if Is_Array_Type (LT) and then (RT = LT or else RT = Base_Type (Component_Type (LT))) then Add_One_Interp (N, Op_Id, LT); elsif Is_Array_Type (RT) and then LT = Base_Type (Component_Type (RT)) then Add_One_Interp (N, Op_Id, RT); -- If one operand is a string type or a user-defined array type, -- and the other is a literal, result is of the specific type. elsif (Root_Type (LT) = Standard_String or else Scope (LT) /= Standard_Standard) and then Etype (R) = Any_String and then not Is_Component_Left_Opnd (N) then Add_One_Interp (N, Op_Id, LT); elsif (Root_Type (RT) = Standard_String or else Scope (RT) /= Standard_Standard) and then Etype (L) = Any_String and then not Is_Component_Right_Opnd (N) then Add_One_Interp (N, Op_Id, RT); elsif not Is_Generic_Type (Etype (Op_Id)) then Add_One_Interp (N, Op_Id, Etype (Op_Id)); else -- Type and its operations must be visible Set_Entity (N, Empty); Analyze_Concatenation (N); end if; else Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; else Op_Id := Get_Name_Entity_Id (Name_Op_Concat); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator then -- Do not consider operators declared in dead code, they -- cannot be part of the resolution. if Is_Eliminated (Op_Id) then null; else Find_Concatenation_Types (L, R, Op_Id, N); end if; else Analyze_User_Defined_Binary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; end if; Operator_Check (N); end Analyze_Concatenation_Rest; ------------------------------------ -- Analyze_Comparison_Equality_Op -- ------------------------------------ procedure Analyze_Comparison_Equality_Op (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); L : constant Node_Id := Left_Opnd (N); R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id; begin Set_Etype (N, Any_Type); Candidate_Type := Empty; Analyze_Expression (L); Analyze_Expression (R); -- If the entity is set, the node is a generic instance with a non-local -- reference to the predefined operator or to a user-defined function. -- It can also be an inequality that is expanded into the negation of a -- call to a user-defined equality operator. -- For the predefined case, the result is Boolean, regardless of the -- type of the operands. The operands may even be limited, if they are -- generic actuals. If they are overloaded, label the operands with the -- compare type if it is present, typically because it is a global type -- in a generic instance, or with the common type that must be present, -- or with the type of the formal of the user-defined function. if Present (Entity (N)) then Op_Id := Entity (N); if Ekind (Op_Id) = E_Operator then Add_One_Interp (N, Op_Id, Standard_Boolean); else Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; if Is_Overloaded (L) then if Ekind (Op_Id) = E_Operator then Set_Etype (L, (if Present (Compare_Type (N)) then Compare_Type (N) else Intersect_Types (L, R))); else Set_Etype (L, Etype (First_Formal (Op_Id))); end if; end if; if Is_Overloaded (R) then if Ekind (Op_Id) = E_Operator then Set_Etype (R, (if Present (Compare_Type (N)) then Compare_Type (N) else Intersect_Types (L, R))); else Set_Etype (R, Etype (Next_Formal (First_Formal (Op_Id)))); end if; end if; else Op_Id := Get_Name_Entity_Id (Chars (N)); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator then Find_Comparison_Equality_Types (L, R, Op_Id, N); else Analyze_User_Defined_Binary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; end if; -- If there was no match and the operator is inequality, this may be -- a case where inequality has not been made explicit, as for tagged -- types. Analyze the node as the negation of an equality operation. -- This cannot be done earlier because, before analysis, we cannot rule -- out the presence of an explicit inequality. if Etype (N) = Any_Type and then Nkind (N) = N_Op_Ne then Op_Id := Get_Name_Entity_Id (Name_Op_Eq); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator then Find_Comparison_Equality_Types (L, R, Op_Id, N); else Analyze_User_Defined_Binary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; if Etype (N) /= Any_Type then Op_Id := Entity (N); Rewrite (N, Make_Op_Not (Loc, Right_Opnd => Make_Op_Eq (Loc, Left_Opnd => Left_Opnd (N), Right_Opnd => Right_Opnd (N)))); Set_Entity (Right_Opnd (N), Op_Id); Analyze (N); end if; end if; Operator_Check (N); Check_Function_Writable_Actuals (N); end Analyze_Comparison_Equality_Op; ---------------------------------- -- Analyze_Explicit_Dereference -- ---------------------------------- procedure Analyze_Explicit_Dereference (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); P : constant Node_Id := Prefix (N); T : Entity_Id; I : Interp_Index; It : Interp; New_N : Node_Id; function Is_Function_Type return Boolean; -- Check whether node may be interpreted as an implicit function call ---------------------- -- Is_Function_Type -- ---------------------- function Is_Function_Type return Boolean is I : Interp_Index; It : Interp; begin if not Is_Overloaded (N) then return Ekind (Base_Type (Etype (N))) = E_Subprogram_Type and then Etype (Base_Type (Etype (N))) /= Standard_Void_Type; else Get_First_Interp (N, I, It); while Present (It.Nam) loop if Ekind (Base_Type (It.Typ)) /= E_Subprogram_Type or else Etype (Base_Type (It.Typ)) = Standard_Void_Type then return False; end if; Get_Next_Interp (I, It); end loop; return True; end if; end Is_Function_Type; -- Start of processing for Analyze_Explicit_Dereference begin -- In formal verification mode, keep track of all reads and writes -- through explicit dereferences. if GNATprove_Mode then SPARK_Specific.Generate_Dereference (N); end if; Analyze (P); Set_Etype (N, Any_Type); -- Test for remote access to subprogram type, and if so return -- after rewriting the original tree. if Remote_AST_E_Dereference (P) then return; end if; -- Normal processing for other than remote access to subprogram type if not Is_Overloaded (P) then if Is_Access_Type (Etype (P)) then -- Set the Etype declare DT : constant Entity_Id := Designated_Type (Etype (P)); begin -- An explicit dereference is a legal occurrence of an -- incomplete type imported through a limited_with clause, if -- the full view is visible, or if we are within an instance -- body, where the enclosing body has a regular with_clause -- on the unit. if From_Limited_With (DT) and then not From_Limited_With (Scope (DT)) and then (Is_Immediately_Visible (Scope (DT)) or else (Is_Child_Unit (Scope (DT)) and then Is_Visible_Lib_Unit (Scope (DT))) or else In_Instance_Body) then Set_Etype (N, Available_View (DT)); else Set_Etype (N, DT); end if; end; elsif Etype (P) /= Any_Type then Error_Msg_N ("prefix of dereference must be an access type", N); return; end if; else Get_First_Interp (P, I, It); while Present (It.Nam) loop T := It.Typ; if Is_Access_Type (T) then Add_One_Interp (N, Designated_Type (T), Designated_Type (T)); end if; Get_Next_Interp (I, It); end loop; -- Error if no interpretation of the prefix has an access type if Etype (N) = Any_Type then Error_Msg_N ("access type required in prefix of explicit dereference", P); Set_Etype (N, Any_Type); return; end if; end if; if Is_Function_Type and then Nkind (Parent (N)) /= N_Indexed_Component and then (Nkind (Parent (N)) /= N_Function_Call or else N /= Name (Parent (N))) and then (Nkind (Parent (N)) /= N_Procedure_Call_Statement or else N /= Name (Parent (N))) and then Nkind (Parent (N)) /= N_Subprogram_Renaming_Declaration and then (Nkind (Parent (N)) /= N_Attribute_Reference or else (Attribute_Name (Parent (N)) /= Name_Address and then Attribute_Name (Parent (N)) /= Name_Access)) then -- Name is a function call with no actuals, in a context that -- requires deproceduring (including as an actual in an enclosing -- function or procedure call). There are some pathological cases -- where the prefix might include functions that return access to -- subprograms and others that return a regular type. Disambiguation -- of those has to take place in Resolve. New_N := Make_Function_Call (Loc, Name => Make_Explicit_Dereference (Loc, P), Parameter_Associations => New_List); -- If the prefix is overloaded, remove operations that have formals, -- we know that this is a parameterless call. if Is_Overloaded (P) then Get_First_Interp (P, I, It); while Present (It.Nam) loop T := It.Typ; if Is_Access_Type (T) and then No (First_Formal (Base_Type (Designated_Type (T)))) then Set_Etype (P, T); else Remove_Interp (I); end if; Get_Next_Interp (I, It); end loop; end if; Rewrite (N, New_N); Analyze (N); elsif not Is_Function_Type and then Is_Overloaded (N) then -- The prefix may include access to subprograms and other access -- types. If the context selects the interpretation that is a -- function call (not a procedure call) we cannot rewrite the node -- yet, but we include the result of the call interpretation. Get_First_Interp (N, I, It); while Present (It.Nam) loop if Ekind (Base_Type (It.Typ)) = E_Subprogram_Type and then Etype (Base_Type (It.Typ)) /= Standard_Void_Type and then Nkind (Parent (N)) /= N_Procedure_Call_Statement then Add_One_Interp (N, Etype (It.Typ), Etype (It.Typ)); end if; Get_Next_Interp (I, It); end loop; end if; -- A value of remote access-to-class-wide must not be dereferenced -- (RM E.2.2(16)). Validate_Remote_Access_To_Class_Wide_Type (N); end Analyze_Explicit_Dereference; ------------------------ -- Analyze_Expression -- ------------------------ procedure Analyze_Expression (N : Node_Id) is begin -- If the expression is an indexed component that will be rewritten -- as a container indexing, it has already been analyzed. if Nkind (N) = N_Indexed_Component and then Present (Generalized_Indexing (N)) then null; else Analyze (N); Check_Parameterless_Call (N); end if; end Analyze_Expression; ------------------------------------- -- Analyze_Expression_With_Actions -- ------------------------------------- procedure Analyze_Expression_With_Actions (N : Node_Id) is procedure Check_Action_OK (A : Node_Id); -- Check that the action A is allowed as a declare_item of a declare -- expression if N and A come from source. --------------------- -- Check_Action_OK -- --------------------- procedure Check_Action_OK (A : Node_Id) is begin if not Comes_From_Source (N) or else not Comes_From_Source (A) then -- If, for example, an (illegal) expression function is -- transformed into a "vanilla" function then we don't want to -- allow it just because Comes_From_Source is now False. So look -- at the Original_Node. if Is_Rewrite_Substitution (A) then Check_Action_OK (Original_Node (A)); end if; return; -- Allow anything in generated code end if; case Nkind (A) is when N_Object_Declaration => if Nkind (Object_Definition (A)) = N_Access_Definition then Error_Msg_N ("anonymous access type not allowed in declare_expression", Object_Definition (A)); end if; if Aliased_Present (A) then Error_Msg_N ("ALIASED not allowed in declare_expression", A); end if; if Constant_Present (A) and then not Is_Limited_Type (Etype (Defining_Identifier (A))) then return; -- nonlimited constants are OK end if; when N_Object_Renaming_Declaration => if Present (Access_Definition (A)) then Error_Msg_N ("anonymous access type not allowed in declare_expression", Access_Definition (A)); end if; if not Is_Limited_Type (Etype (Defining_Identifier (A))) then return; -- ???For now; the RM rule is a bit more complicated end if; when N_Pragma => declare -- See AI22-0045 pragma categorization. subtype Executable_Pragma_Id is Pragma_Id with Predicate => Executable_Pragma_Id in -- language-defined executable pragmas Pragma_Assert | Pragma_Inspection_Point -- GNAT-defined executable pragmas | Pragma_Assume | Pragma_Debug; begin if Get_Pragma_Id (A) in Executable_Pragma_Id then return; end if; end; when others => null; -- Nothing else allowed end case; -- We could mention pragmas in the message text; let's not. Error_Msg_N ("object renaming or constant declaration expected", A); end Check_Action_OK; A : Node_Id; EWA_Scop : Entity_Id; -- Start of processing for Analyze_Expression_With_Actions begin -- Create a scope, which is needed to provide proper visibility of the -- declare_items. EWA_Scop := New_Internal_Entity (E_Block, Current_Scope, Sloc (N), 'B'); Set_Etype (EWA_Scop, Standard_Void_Type); Set_Scope (EWA_Scop, Current_Scope); Set_Parent (EWA_Scop, N); Push_Scope (EWA_Scop); -- If this Expression_With_Actions node comes from source, then it -- represents a declare_expression; increment the counter to take note -- of that. if Comes_From_Source (N) then In_Declare_Expr := In_Declare_Expr + 1; end if; A := First (Actions (N)); while Present (A) loop Analyze (A); Check_Action_OK (A); Next (A); end loop; Analyze_Expression (Expression (N)); Set_Etype (N, Etype (Expression (N))); End_Scope; if Comes_From_Source (N) then In_Declare_Expr := In_Declare_Expr - 1; end if; end Analyze_Expression_With_Actions; --------------------------- -- Analyze_If_Expression -- --------------------------- procedure Analyze_If_Expression (N : Node_Id) is Condition : constant Node_Id := First (Expressions (N)); Then_Expr : Node_Id; Else_Expr : Node_Id; procedure Check_Else_Expression (T : Entity_Id); -- Check one interpretation of the THEN expression with type T procedure Check_Expression_Pair (T1, T2 : Entity_Id); -- Check THEN expression with type T1 and ELSE expression with type T2 --------------------------- -- Check_Else_Expression -- --------------------------- procedure Check_Else_Expression (T : Entity_Id) is I : Interp_Index; It : Interp; begin -- Loop through the interpretations of the ELSE expression if not Is_Overloaded (Else_Expr) then Check_Expression_Pair (T, Etype (Else_Expr)); else Get_First_Interp (Else_Expr, I, It); while Present (It.Typ) loop Check_Expression_Pair (T, It.Typ); Get_Next_Interp (I, It); end loop; end if; end Check_Else_Expression; --------------------------- -- Check_Expression_Pair -- --------------------------- procedure Check_Expression_Pair (T1, T2 : Entity_Id) is T : Entity_Id; begin if Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1) then T := Specific_Type (T1, T2); elsif Is_User_Defined_Literal (Then_Expr, T2) then T := T2; elsif Is_User_Defined_Literal (Else_Expr, T1) then T := T1; else T := Possible_Type_For_Conditional_Expression (T1, T2); if No (T) then return; end if; end if; Add_One_Interp (N, T, T); end Check_Expression_Pair; -- Local variables I : Interp_Index; It : Interp; -- Start of processing for Analyze_If_Expression begin -- Defend against error of missing expressions from previous error if No (Condition) then Check_Error_Detected; return; end if; Set_Etype (N, Any_Type); Then_Expr := Next (Condition); if No (Then_Expr) then Check_Error_Detected; return; end if; Else_Expr := Next (Then_Expr); -- Analyze and resolve the condition. We need to resolve this now so -- that it gets folded to True/False if possible, before we analyze -- the THEN/ELSE branches, because when analyzing these branches, we -- may call Is_Statically_Unevaluated, which expects the condition of -- an enclosing IF to have been analyze/resolved/evaluated. Analyze_Expression (Condition); Resolve (Condition, Any_Boolean); -- Analyze the THEN expression and (if present) the ELSE expression. For -- them we delay resolution in the normal manner because of overloading. Analyze_Expression (Then_Expr); if Present (Else_Expr) then Analyze_Expression (Else_Expr); end if; -- RM 4.5.7(10/3): If the if_expression is the operand of a type -- conversion, the type of the if_expression is the target type -- of the conversion. if Nkind (Parent (N)) = N_Type_Conversion then Set_Etype (N, Etype (Parent (N))); return; end if; -- Loop through the interpretations of the THEN expression and check the -- ELSE expression if present. if not Is_Overloaded (Then_Expr) then if Present (Else_Expr) then Check_Else_Expression (Etype (Then_Expr)); else Set_Etype (N, Etype (Then_Expr)); end if; else Get_First_Interp (Then_Expr, I, It); while Present (It.Typ) loop if Present (Else_Expr) then Check_Else_Expression (It.Typ); else Add_One_Interp (N, It.Typ, It.Typ); end if; Get_Next_Interp (I, It); end loop; end if; -- If no possible interpretation has been found, the type of the -- ELSE expression does not match any interpretation of the THEN -- expression. if Etype (N) = Any_Type then if Is_Overloaded (Then_Expr) then if Is_Overloaded (Else_Expr) then Error_Msg_N ("no interpretation compatible with those of THEN expression", Else_Expr); else Error_Msg_N ("type of ELSE incompatible with interpretations of THEN " & "expression", Else_Expr); Error_Msg_NE ("\ELSE expression has}!", Else_Expr, Etype (Else_Expr)); end if; elsif Present (Else_Expr) then if Is_Overloaded (Else_Expr) then Error_Msg_N ("no interpretation compatible with type of THEN expression", Else_Expr); Error_Msg_NE ("\THEN expression has}!", Else_Expr, Etype (Then_Expr)); else Error_Msg_N ("type of ELSE incompatible with that of THEN expression", Else_Expr); Error_Msg_NE ("\THEN expression has}!", Else_Expr, Etype (Then_Expr)); Error_Msg_NE ("\ELSE expression has}!", Else_Expr, Etype (Else_Expr)); end if; end if; end if; end Analyze_If_Expression; ------------------------------------ -- Analyze_Indexed_Component_Form -- ------------------------------------ procedure Analyze_Indexed_Component_Form (N : Node_Id) is P : constant Node_Id := Prefix (N); Exprs : constant List_Id := Expressions (N); Exp : Node_Id; P_T : Entity_Id; E : Node_Id; U_N : Entity_Id; procedure Process_Function_Call; -- Prefix in indexed component form is an overloadable entity, so the -- node is very likely a function call; reformat it as such. The only -- exception is a call to a parameterless function that returns an -- array type, or an access type thereof, in which case this will be -- undone later by Resolve_Call or Resolve_Entry_Call. procedure Process_Indexed_Component; -- Prefix in indexed component form is actually an indexed component. -- This routine processes it, knowing that the prefix is already -- resolved. procedure Process_Indexed_Component_Or_Slice; -- An indexed component with a single index may designate a slice if -- the index is a subtype mark. This routine disambiguates these two -- cases by resolving the prefix to see if it is a subtype mark. procedure Process_Overloaded_Indexed_Component; -- If the prefix of an indexed component is overloaded, the proper -- interpretation is selected by the index types and the context. --------------------------- -- Process_Function_Call -- --------------------------- procedure Process_Function_Call is Loc : constant Source_Ptr := Sloc (N); Actual : Node_Id; begin Change_Node (N, N_Function_Call); Set_Name (N, P); Set_Parameter_Associations (N, Exprs); -- Analyze actuals prior to analyzing the call itself Actual := First (Parameter_Associations (N)); while Present (Actual) loop Analyze (Actual); Check_Parameterless_Call (Actual); -- Move to next actual. Note that we use Next, not Next_Actual -- here. The reason for this is a bit subtle. If a function call -- includes named associations, the parser recognizes the node -- as a call, and it is analyzed as such. If all associations are -- positional, the parser builds an indexed_component node, and -- it is only after analysis of the prefix that the construct -- is recognized as a call, in which case Process_Function_Call -- rewrites the node and analyzes the actuals. If the list of -- actuals is malformed, the parser may leave the node as an -- indexed component (despite the presence of named associations). -- The iterator Next_Actual is equivalent to Next if the list is -- positional, but follows the normalized chain of actuals when -- named associations are present. In this case normalization has -- not taken place, and actuals remain unanalyzed, which leads to -- subsequent crashes or loops if there is an attempt to continue -- analysis of the program. -- IF there is a single actual and it is a type name, the node -- can only be interpreted as a slice of a parameterless call. -- Rebuild the node as such and analyze. if No (Next (Actual)) and then Is_Entity_Name (Actual) and then Is_Type (Entity (Actual)) and then Is_Discrete_Type (Entity (Actual)) and then not Is_Current_Instance (Actual) then Replace (N, Make_Slice (Loc, Prefix => P, Discrete_Range => New_Occurrence_Of (Entity (Actual), Loc))); Analyze (N); return; else Next (Actual); end if; end loop; Analyze_Call (N); end Process_Function_Call; ------------------------------- -- Process_Indexed_Component -- ------------------------------- procedure Process_Indexed_Component is Exp : Node_Id; Array_Type : Entity_Id; Index : Node_Id; Pent : Entity_Id := Empty; begin Exp := First (Exprs); if Is_Overloaded (P) then Process_Overloaded_Indexed_Component; else Array_Type := Etype (P); if Is_Entity_Name (P) then Pent := Entity (P); elsif Nkind (P) = N_Selected_Component and then Is_Entity_Name (Selector_Name (P)) then Pent := Entity (Selector_Name (P)); end if; -- Prefix must be appropriate for an array type, taking into -- account a possible implicit dereference. if Is_Access_Type (Array_Type) then Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); Array_Type := Implicitly_Designated_Type (Array_Type); end if; if Is_Array_Type (Array_Type) then -- In order to correctly access First_Index component later, -- replace string literal subtype by its parent type. if Ekind (Array_Type) = E_String_Literal_Subtype then Array_Type := Etype (Array_Type); end if; elsif Present (Pent) and then Ekind (Pent) = E_Entry_Family then Analyze (Exp); Set_Etype (N, Any_Type); if not Has_Compatible_Type (Exp, Entry_Index_Type (Pent)) then Error_Msg_N ("invalid index type in entry name", N); elsif Present (Next (Exp)) then Error_Msg_N ("too many subscripts in entry reference", N); else Set_Etype (N, Etype (P)); end if; return; elsif Is_Record_Type (Array_Type) and then Remote_AST_I_Dereference (P) then return; elsif Try_Container_Indexing (N, P, Exprs) then return; elsif Array_Type = Any_Type then Set_Etype (N, Any_Type); -- In most cases the analysis of the prefix will have emitted -- an error already, but if the prefix may be interpreted as a -- call in prefixed notation, the report is left to the caller. -- To prevent cascaded errors, report only if no previous ones. if Serious_Errors_Detected = 0 then Error_Msg_N ("invalid prefix in indexed component", P); if Nkind (P) = N_Expanded_Name then Error_Msg_NE ("\& is not visible", P, Selector_Name (P)); end if; end if; return; -- Here we definitely have a bad indexing else if Nkind (Parent (N)) = N_Requeue_Statement and then Present (Pent) and then Ekind (Pent) = E_Entry then Error_Msg_N ("REQUEUE does not permit parameters", First (Exprs)); elsif Is_Entity_Name (P) and then Etype (P) = Standard_Void_Type then Error_Msg_NE ("incorrect use of &", P, Entity (P)); else Error_Msg_N ("array type required in indexed component", P); end if; Set_Etype (N, Any_Type); return; end if; Index := First_Index (Array_Type); while Present (Index) and then Present (Exp) loop if not Has_Compatible_Type (Exp, Etype (Index)) then Wrong_Type (Exp, Etype (Index)); Set_Etype (N, Any_Type); return; end if; Next_Index (Index); Next (Exp); end loop; Set_Etype (N, Component_Type (Array_Type)); Check_Implicit_Dereference (N, Etype (N)); -- Generate conversion to class-wide type if Is_Mutably_Tagged_CW_Equivalent_Type (Etype (N)) then Make_Mutably_Tagged_Conversion (N); end if; if Present (Index) then Error_Msg_N ("too few subscripts in array reference", First (Exprs)); elsif Present (Exp) then Error_Msg_N ("too many subscripts in array reference", Exp); end if; end if; end Process_Indexed_Component; ---------------------------------------- -- Process_Indexed_Component_Or_Slice -- ---------------------------------------- procedure Process_Indexed_Component_Or_Slice is begin Exp := First (Exprs); while Present (Exp) loop Analyze_Expression (Exp); Next (Exp); end loop; Exp := First (Exprs); -- If one index is present, and it is a subtype name, then the node -- denotes a slice (note that the case of an explicit range for a -- slice was already built as an N_Slice node in the first place, -- so that case is not handled here). -- We use a replace rather than a rewrite here because this is one -- of the cases in which the tree built by the parser is plain wrong. if No (Next (Exp)) and then Is_Entity_Name (Exp) and then Is_Type (Entity (Exp)) then Replace (N, Make_Slice (Sloc (N), Prefix => P, Discrete_Range => New_Copy (Exp))); Analyze (N); -- Otherwise (more than one index present, or single index is not -- a subtype name), then we have the indexed component case. else Process_Indexed_Component; end if; end Process_Indexed_Component_Or_Slice; ------------------------------------------ -- Process_Overloaded_Indexed_Component -- ------------------------------------------ procedure Process_Overloaded_Indexed_Component is Exp : Node_Id; I : Interp_Index; It : Interp; Typ : Entity_Id; Index : Node_Id; Found : Boolean; begin Set_Etype (N, Any_Type); Get_First_Interp (P, I, It); while Present (It.Nam) loop Typ := It.Typ; if Is_Access_Type (Typ) then Typ := Designated_Type (Typ); Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); end if; if Is_Array_Type (Typ) then -- Got a candidate: verify that index types are compatible Index := First_Index (Typ); Found := True; Exp := First (Exprs); while Present (Index) and then Present (Exp) loop if Has_Compatible_Type (Exp, Etype (Index)) then null; else Found := False; Remove_Interp (I); exit; end if; Next_Index (Index); Next (Exp); end loop; if Found and then No (Index) and then No (Exp) then declare CT : constant Entity_Id := Base_Type (Component_Type (Typ)); begin Add_One_Interp (N, CT, CT); Check_Implicit_Dereference (N, CT); end; end if; elsif Try_Container_Indexing (N, P, Exprs) then return; end if; Get_Next_Interp (I, It); end loop; if Etype (N) = Any_Type then Error_Msg_N ("no legal interpretation for indexed component", N); Set_Is_Overloaded (N, False); end if; end Process_Overloaded_Indexed_Component; -- Start of processing for Analyze_Indexed_Component_Form begin -- Get name of array, function or type Analyze (P); -- If P is an explicit dereference whose prefix is of a remote access- -- to-subprogram type, then N has already been rewritten as a subprogram -- call and analyzed. if Nkind (N) in N_Subprogram_Call then return; -- When the prefix is attribute 'Loop_Entry and the sole expression of -- the indexed component denotes a loop name, the indexed form is turned -- into an attribute reference. elsif Nkind (N) = N_Attribute_Reference and then Attribute_Name (N) = Name_Loop_Entry then return; end if; pragma Assert (Nkind (N) = N_Indexed_Component); P_T := Base_Type (Etype (P)); if Is_Entity_Name (P) and then Present (Entity (P)) then U_N := Entity (P); if Is_Type (U_N) then -- Reformat node as a type conversion E := Remove_Head (Exprs); if Present (First (Exprs)) then Error_Msg_N ("argument of type conversion must be single expression", N); end if; Change_Node (N, N_Type_Conversion); Set_Subtype_Mark (N, P); Set_Etype (N, U_N); Set_Expression (N, E); -- After changing the node, call for the specific Analysis -- routine directly, to avoid a double call to the expander. Analyze_Type_Conversion (N); return; end if; if Is_Overloadable (U_N) then Process_Function_Call; elsif Ekind (Etype (P)) = E_Subprogram_Type or else (Is_Access_Type (Etype (P)) and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type) then -- Call to access_to-subprogram with possible implicit dereference Process_Function_Call; elsif Is_Generic_Subprogram (U_N) then -- A common beginner's (or C++ templates fan) error Error_Msg_N ("generic subprogram cannot be called", N); Set_Etype (N, Any_Type); return; else Process_Indexed_Component_Or_Slice; end if; -- If not an entity name, prefix is an expression that may denote -- an array or an access-to-subprogram. else if Ekind (P_T) = E_Subprogram_Type or else (Is_Access_Type (P_T) and then Ekind (Designated_Type (P_T)) = E_Subprogram_Type) then Process_Function_Call; elsif Nkind (P) = N_Selected_Component and then Present (Entity (Selector_Name (P))) and then Is_Overloadable (Entity (Selector_Name (P))) then Process_Function_Call; else -- Indexed component, slice, or a call to a member of a family -- entry, which will be converted to an entry call later. Process_Indexed_Component_Or_Slice; end if; end if; Analyze_Dimension (N); end Analyze_Indexed_Component_Form; ------------------------ -- Analyze_Logical_Op -- ------------------------ procedure Analyze_Logical_Op (N : Node_Id) is L : constant Node_Id := Left_Opnd (N); R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id; begin Set_Etype (N, Any_Type); Candidate_Type := Empty; Analyze_Expression (L); Analyze_Expression (R); -- If the entity is already set, the node is the instantiation of a -- generic node with a non-local reference, or was manufactured by a -- call to Make_Op_xxx. In either case the entity is known to be valid, -- and we do not need to collect interpretations, instead we just get -- the single possible interpretation. if Present (Entity (N)) then Op_Id := Entity (N); if Ekind (Op_Id) = E_Operator then Find_Boolean_Types (L, R, Op_Id, N); else Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; -- Entity is not already set, so we do need to collect interpretations else Op_Id := Get_Name_Entity_Id (Chars (N)); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator then Find_Boolean_Types (L, R, Op_Id, N); else Analyze_User_Defined_Binary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; end if; Operator_Check (N); Check_Function_Writable_Actuals (N); if Style_Check then if Nkind (L) not in N_Short_Circuit | N_Op_And | N_Op_Or | N_Op_Xor and then Is_Boolean_Type (Etype (L)) then Check_Xtra_Parens_Precedence (L); end if; if Nkind (R) not in N_Short_Circuit | N_Op_And | N_Op_Or | N_Op_Xor and then Is_Boolean_Type (Etype (R)) then Check_Xtra_Parens_Precedence (R); end if; end if; end Analyze_Logical_Op; --------------------------- -- Analyze_Membership_Op -- --------------------------- procedure Analyze_Membership_Op (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); L : constant Node_Id := Left_Opnd (N); R : constant Node_Id := Right_Opnd (N); procedure Analyze_Set_Membership; -- If a set of alternatives is present, analyze each and find the -- common type to which they must all resolve. function Find_Interp return Boolean; -- Find a valid interpretation of the test. Note that the context of the -- operation plays no role in resolving the operands, so that if there -- is more than one interpretation of the operands that is compatible -- with the test, the operation is ambiguous. function Try_Left_Interp (T : Entity_Id) return Boolean; -- Try an interpretation of the left operand with type T. Return true if -- one interpretation (at least) of the right operand making up a valid -- operand pair exists, otherwise false if no such pair exists. function Is_Valid_Pair (T1, T2 : Entity_Id) return Boolean; -- Return true if T1 and T2 constitute a valid pair of operand types for -- L and R respectively. ---------------------------- -- Analyze_Set_Membership -- ---------------------------- procedure Analyze_Set_Membership is Alt : Node_Id; Index : Interp_Index; It : Interp; Candidate_Interps : Node_Id; Common_Type : Entity_Id := Empty; begin Analyze (L); Candidate_Interps := L; if not Is_Overloaded (L) then Common_Type := Etype (L); Alt := First (Alternatives (N)); while Present (Alt) loop Analyze (Alt); if not Has_Compatible_Type (Alt, Common_Type) then Wrong_Type (Alt, Common_Type); end if; Next (Alt); end loop; else Alt := First (Alternatives (N)); while Present (Alt) loop Analyze (Alt); if not Is_Overloaded (Alt) then Common_Type := Etype (Alt); else Get_First_Interp (Alt, Index, It); while Present (It.Typ) loop if not Has_Compatible_Type (Candidate_Interps, It.Typ) then Remove_Interp (Index); end if; Get_Next_Interp (Index, It); end loop; Get_First_Interp (Alt, Index, It); if No (It.Typ) then Error_Msg_N ("alternative has no legal type", Alt); return; end if; -- If alternative is not overloaded, we have a unique type -- for all of them. Set_Etype (Alt, It.Typ); -- If the alternative is an enumeration literal, use the one -- for this interpretation. if Is_Entity_Name (Alt) then Set_Entity (Alt, It.Nam); end if; Get_Next_Interp (Index, It); if No (It.Typ) then Set_Is_Overloaded (Alt, False); Common_Type := Etype (Alt); end if; Candidate_Interps := Alt; end if; Next (Alt); end loop; end if; if Present (Common_Type) then Set_Etype (L, Common_Type); -- The left operand may still be overloaded, to be resolved using -- the Common_Type. else Error_Msg_N ("cannot resolve membership operation", N); end if; end Analyze_Set_Membership; ----------------- -- Find_Interp -- ----------------- function Find_Interp return Boolean is Found : Boolean; I : Interp_Index; It : Interp; L_Typ : Entity_Id; Valid_I : Interp_Index; begin -- Loop through the interpretations of the left operand if not Is_Overloaded (L) then Found := Try_Left_Interp (Etype (L)); else Found := False; L_Typ := Empty; Valid_I := 0; Get_First_Interp (L, I, It); while Present (It.Typ) loop if Try_Left_Interp (It.Typ) then -- If several interpretations are possible, disambiguate if Present (L_Typ) and then Base_Type (It.Typ) /= Base_Type (L_Typ) then It := Disambiguate (L, Valid_I, I, Any_Type); if It = No_Interp then Ambiguous_Operands (N); Set_Etype (L, Any_Type); return True; end if; else Valid_I := I; end if; L_Typ := It.Typ; Set_Etype (L, L_Typ); Found := True; end if; Get_Next_Interp (I, It); end loop; end if; return Found; end Find_Interp; --------------------- -- Try_Left_Interp -- --------------------- function Try_Left_Interp (T : Entity_Id) return Boolean is Found : Boolean; I : Interp_Index; It : Interp; R_Typ : Entity_Id; Valid_I : Interp_Index; begin -- Defend against previous error if Nkind (R) = N_Error then Found := False; -- Loop through the interpretations of the right operand elsif not Is_Overloaded (R) then Found := Is_Valid_Pair (T, Etype (R)); else Found := False; R_Typ := Empty; Valid_I := 0; Get_First_Interp (R, I, It); while Present (It.Typ) loop if Is_Valid_Pair (T, It.Typ) then -- If several interpretations are possible, disambiguate if Present (R_Typ) and then Base_Type (It.Typ) /= Base_Type (R_Typ) then It := Disambiguate (R, Valid_I, I, Any_Type); if It = No_Interp then Ambiguous_Operands (N); Set_Etype (R, Any_Type); return True; end if; else Valid_I := I; end if; R_Typ := It.Typ; Found := True; end if; Get_Next_Interp (I, It); end loop; end if; return Found; end Try_Left_Interp; ------------------- -- Is_Valid_Pair -- ------------------- function Is_Valid_Pair (T1, T2 : Entity_Id) return Boolean is begin return Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1) or else Is_User_Defined_Literal (L, T2) or else Is_User_Defined_Literal (R, T1); end Is_Valid_Pair; -- Local variables Dummy : Boolean; Op : Node_Id; -- Start of processing for Analyze_Membership_Op begin Analyze_Expression (L); if No (R) then pragma Assert (Ada_Version >= Ada_2012); Analyze_Set_Membership; declare Alt : Node_Id; begin Alt := First (Alternatives (N)); while Present (Alt) loop if Is_Entity_Name (Alt) and then Is_Type (Entity (Alt)) then Check_Fully_Declared (Entity (Alt), Alt); if Has_Ghost_Predicate_Aspect (Entity (Alt)) then Error_Msg_NE ("subtype& has ghost predicate, " & "not allowed in membership test", Alt, Entity (Alt)); end if; end if; Next (Alt); end loop; end; elsif Nkind (R) = N_Range or else (Nkind (R) = N_Attribute_Reference and then Attribute_Name (R) = Name_Range) then Analyze_Expression (R); Dummy := Find_Interp; -- If not a range, it can be a subtype mark, or else it is a degenerate -- membership test with a singleton value, i.e. a test for equality, -- if the types are compatible. else Analyze_Expression (R); if Is_Entity_Name (R) and then Is_Type (Entity (R)) then Find_Type (R); Check_Fully_Declared (Entity (R), R); if Has_Ghost_Predicate_Aspect (Entity (R)) then Error_Msg_NE ("subtype& has ghost predicate, " & "not allowed in membership test", R, Entity (R)); end if; elsif Ada_Version >= Ada_2012 and then Find_Interp then Op := Make_Op_Eq (Loc, Left_Opnd => L, Right_Opnd => R); Resolve_Membership_Equality (Op, Etype (L)); if Nkind (N) = N_Not_In then Op := Make_Op_Not (Loc, Op); end if; Rewrite (N, Op); Analyze (N); return; else -- In all versions of the language, if we reach this point there -- is a previous error that will be diagnosed below. Find_Type (R); end if; end if; -- Compatibility between expression and subtype mark or range is -- checked during resolution. The result of the operation is Boolean -- in any case. Set_Etype (N, Standard_Boolean); if Comes_From_Source (N) and then Present (Right_Opnd (N)) and then Is_CPP_Class (Etype (Etype (Right_Opnd (N)))) then Error_Msg_N ("membership test not applicable to cpp-class types", N); end if; Check_Function_Writable_Actuals (N); end Analyze_Membership_Op; ----------------- -- Analyze_Mod -- ----------------- procedure Analyze_Mod (N : Node_Id) is begin -- A special warning check, if we have an expression of the form: -- expr mod 2 * literal -- where literal is 128 or less, then probably what was meant was -- expr mod 2 ** literal -- so issue an appropriate warning. if Warn_On_Suspicious_Modulus_Value and then Nkind (Right_Opnd (N)) = N_Integer_Literal and then Intval (Right_Opnd (N)) = Uint_2 and then Nkind (Parent (N)) = N_Op_Multiply and then Nkind (Right_Opnd (Parent (N))) = N_Integer_Literal and then Intval (Right_Opnd (Parent (N))) <= Uint_128 then Error_Msg_N ("suspicious MOD value, was '*'* intended'??.m?", Parent (N)); end if; -- Remaining processing is same as for other arithmetic operators Analyze_Arithmetic_Op (N); end Analyze_Mod; ---------------------- -- Analyze_Negation -- ---------------------- procedure Analyze_Negation (N : Node_Id) is R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id; begin Set_Etype (N, Any_Type); Candidate_Type := Empty; Analyze_Expression (R); -- If the entity is already set, the node is the instantiation of a -- generic node with a non-local reference, or was manufactured by a -- call to Make_Op_xxx. In either case the entity is known to be valid, -- and we do not need to collect interpretations, instead we just get -- the single possible interpretation. if Present (Entity (N)) then Op_Id := Entity (N); if Ekind (Op_Id) = E_Operator then Find_Negation_Types (R, Op_Id, N); else Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; else Op_Id := Get_Name_Entity_Id (Chars (N)); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator then Find_Negation_Types (R, Op_Id, N); else Analyze_User_Defined_Unary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; end if; Operator_Check (N); end Analyze_Negation; ------------------ -- Analyze_Null -- ------------------ procedure Analyze_Null (N : Node_Id) is begin Set_Etype (N, Universal_Access); end Analyze_Null; ---------------------- -- Analyze_One_Call -- ---------------------- procedure Analyze_One_Call (N : Node_Id; Nam : Entity_Id; Report : Boolean; Success : out Boolean; Skip_First : Boolean := False) is Actuals : constant List_Id := Parameter_Associations (N); Prev_T : constant Entity_Id := Etype (N); -- Recognize cases of prefixed calls that have been rewritten in -- various ways. The simplest case is a rewritten selected component, -- but it can also be an already-examined indexed component, or a -- prefix that is itself a rewritten prefixed call that is in turn -- an indexed call (the syntactic ambiguity involving the indexing of -- a function with defaulted parameters that returns an array). -- A flag Maybe_Indexed_Call might be useful here ??? Must_Skip : constant Boolean := Skip_First or else Nkind (Original_Node (N)) = N_Selected_Component or else (Nkind (Original_Node (N)) = N_Indexed_Component and then Nkind (Prefix (Original_Node (N))) = N_Selected_Component) or else (Nkind (Parent (N)) = N_Function_Call and then Is_Array_Type (Etype (Name (N))) and then Etype (Original_Node (N)) = Component_Type (Etype (Name (N))) and then Nkind (Original_Node (Parent (N))) = N_Selected_Component); -- The first formal must be omitted from the match when trying to find -- a primitive operation that is a possible interpretation, and also -- after the call has been rewritten, because the corresponding actual -- is already known to be compatible, and because this may be an -- indexing of a call with default parameters. First_Form : Entity_Id; Formal : Entity_Id; Actual : Node_Id; Is_Indexed : Boolean := False; Is_Indirect : Boolean := False; Subp_Type : constant Entity_Id := Etype (Nam); Norm_OK : Boolean; function Compatible_Types_In_Predicate (T1 : Entity_Id; T2 : Entity_Id) return Boolean; -- For an Ada 2012 predicate or invariant, a call may mention an -- incomplete type, while resolution of the corresponding predicate -- function may see the full view, as a consequence of the delayed -- resolution of the corresponding expressions. This may occur in -- the body of a predicate function, or in a call to such. Anomalies -- involving private and full views can also happen. In each case, -- rewrite node or add conversions to remove spurious type errors. procedure Indicate_Name_And_Type; -- If candidate interpretation matches, indicate name and type of result -- on call node. function Operator_Hidden_By (Fun : Entity_Id) return Boolean; -- There may be a user-defined operator that hides the current -- interpretation. We must check for this independently of the -- analysis of the call with the user-defined operation, because -- the parameter names may be wrong and yet the hiding takes place. -- This fixes a problem with ACATS test B34014O. -- -- When the type Address is a visible integer type, and the DEC -- system extension is visible, the predefined operator may be -- hidden as well, by one of the address operations in auxdec. -- Finally, the abstract operations on address do not hide the -- predefined operator (this is the purpose of making them abstract). ----------------------------------- -- Compatible_Types_In_Predicate -- ----------------------------------- function Compatible_Types_In_Predicate (T1 : Entity_Id; T2 : Entity_Id) return Boolean is function Common_Type (T : Entity_Id) return Entity_Id; -- Find non-private underlying full view if any, without going to -- ancestor type (as opposed to Underlying_Type). ----------------- -- Common_Type -- ----------------- function Common_Type (T : Entity_Id) return Entity_Id is CT : Entity_Id; begin CT := T; if Is_Private_Type (CT) and then Present (Full_View (CT)) then CT := Full_View (CT); end if; if Is_Private_Type (CT) and then Present (Underlying_Full_View (CT)) then CT := Underlying_Full_View (CT); end if; return Base_Type (CT); end Common_Type; -- Start of processing for Compatible_Types_In_Predicate begin if (Ekind (Current_Scope) = E_Function and then Is_Predicate_Function (Current_Scope)) or else (Ekind (Nam) = E_Function and then Is_Predicate_Function (Nam)) then if Is_Incomplete_Type (T1) and then Present (Full_View (T1)) and then Full_View (T1) = T2 then Set_Etype (Formal, Etype (Actual)); return True; elsif Common_Type (T1) = Common_Type (T2) then Rewrite (Actual, Unchecked_Convert_To (Etype (Formal), Actual)); return True; else return False; end if; else return False; end if; end Compatible_Types_In_Predicate; ---------------------------- -- Indicate_Name_And_Type -- ---------------------------- procedure Indicate_Name_And_Type is begin Add_One_Interp (N, Nam, Etype (Nam)); Check_Implicit_Dereference (N, Etype (Nam)); Success := True; -- If the prefix of the call is a name, indicate the entity -- being called. If it is not a name, it is an expression that -- denotes an access to subprogram or else an entry or family. In -- the latter case, the name is a selected component, and the entity -- being called is noted on the selector. if not Is_Type (Nam) then if Is_Entity_Name (Name (N)) then Set_Entity (Name (N), Nam); Set_Etype (Name (N), Etype (Nam)); elsif Nkind (Name (N)) = N_Selected_Component then Set_Entity (Selector_Name (Name (N)), Nam); end if; end if; if Debug_Flag_E and not Report then Write_Str (" Overloaded call "); Write_Int (Int (N)); Write_Str (" compatible with "); Write_Int (Int (Nam)); Write_Eol; end if; end Indicate_Name_And_Type; ------------------------ -- Operator_Hidden_By -- ------------------------ function Operator_Hidden_By (Fun : Entity_Id) return Boolean is Act1 : constant Node_Id := First_Actual (N); Act2 : constant Node_Id := Next_Actual (Act1); Form1 : constant Entity_Id := First_Formal (Fun); Form2 : constant Entity_Id := Next_Formal (Form1); begin if Ekind (Fun) /= E_Function or else Is_Abstract_Subprogram (Fun) then return False; elsif not Has_Compatible_Type (Act1, Etype (Form1)) then return False; elsif Present (Form2) then if No (Act2) or else not Has_Compatible_Type (Act2, Etype (Form2)) then return False; end if; elsif Present (Act2) then return False; end if; -- Now we know that the arity of the operator matches the function, -- and the function call is a valid interpretation. The function -- hides the operator if it has the right signature, or if one of -- its operands is a non-abstract operation on Address when this is -- a visible integer type. return Hides_Op (Fun, Nam) or else Is_Descendant_Of_Address (Etype (Form1)) or else (Present (Form2) and then Is_Descendant_Of_Address (Etype (Form2))); end Operator_Hidden_By; -- Start of processing for Analyze_One_Call begin Success := False; -- If the subprogram has no formals or if all the formals have defaults, -- and the return type is an array type, the node may denote an indexing -- of the result of a parameterless call. In Ada 2005, the subprogram -- may have one non-defaulted formal, and the call may have been written -- in prefix notation, so that the rebuilt parameter list has more than -- one actual. if not Is_Overloadable (Nam) and then Ekind (Nam) /= E_Subprogram_Type and then Ekind (Nam) /= E_Entry_Family then return; end if; -- An indexing requires at least one actual. The name of the call cannot -- be an implicit indirect call, so it cannot be a generated explicit -- dereference. if not Is_Empty_List (Actuals) and then (Needs_No_Actuals (Nam) or else (Needs_One_Actual (Nam) and then Present (Next_Actual (First (Actuals))))) then if Is_Array_Type (Subp_Type) and then (Nkind (Name (N)) /= N_Explicit_Dereference or else Comes_From_Source (Name (N))) then Is_Indexed := Try_Indexed_Call (N, Nam, Subp_Type, Must_Skip); elsif Is_Access_Type (Subp_Type) and then Is_Array_Type (Designated_Type (Subp_Type)) then Is_Indexed := Try_Indexed_Call (N, Nam, Designated_Type (Subp_Type), Must_Skip); -- The prefix can also be a parameterless function that returns an -- access to subprogram, in which case this is an indirect call. -- If this succeeds, an explicit dereference is added later on, -- in Analyze_Call or Resolve_Call. elsif Is_Access_Type (Subp_Type) and then Ekind (Designated_Type (Subp_Type)) = E_Subprogram_Type then Is_Indirect := Try_Indirect_Call (N, Nam, Subp_Type); end if; end if; -- If the call has been transformed into a slice, it is of the form -- F (Subtype) where F is parameterless. The node has been rewritten in -- Try_Indexed_Call and there is nothing else to do. if Is_Indexed and then Nkind (N) = N_Slice then return; end if; Normalize_Actuals (N, Nam, (Report and not Is_Indexed and not Is_Indirect), Norm_OK); if not Norm_OK then -- If an indirect call is a possible interpretation, indicate -- success to the caller. This may be an indexing of an explicit -- dereference of a call that returns an access type (see above). if Is_Indirect or else (Is_Indexed and then Nkind (Name (N)) = N_Explicit_Dereference and then Comes_From_Source (Name (N))) then Success := True; return; -- Mismatch in number or names of parameters elsif Debug_Flag_E then Write_Str (" normalization fails in call "); Write_Int (Int (N)); Write_Str (" with subprogram "); Write_Int (Int (Nam)); Write_Eol; end if; -- If the context expects a function call, discard any interpretation -- that is a procedure. If the node is not overloaded, leave as is for -- better error reporting when type mismatch is found. elsif Nkind (N) = N_Function_Call and then Is_Overloaded (Name (N)) and then Ekind (Nam) = E_Procedure then return; -- Ditto for function calls in a procedure context elsif Nkind (N) = N_Procedure_Call_Statement and then Is_Overloaded (Name (N)) and then Etype (Nam) /= Standard_Void_Type then return; elsif No (Actuals) then -- If Normalize succeeds, then there are default parameters for -- all formals. Indicate_Name_And_Type; elsif Ekind (Nam) = E_Operator then if Nkind (N) = N_Procedure_Call_Statement then return; end if; -- This occurs when the prefix of the call is an operator name -- or an expanded name whose selector is an operator name. Analyze_Operator_Call (N, Nam); if Etype (N) /= Prev_T then -- Check that operator is not hidden by a function interpretation if Is_Overloaded (Name (N)) then declare I : Interp_Index; It : Interp; begin Get_First_Interp (Name (N), I, It); while Present (It.Nam) loop if Operator_Hidden_By (It.Nam) then Set_Etype (N, Prev_T); return; end if; Get_Next_Interp (I, It); end loop; end; end if; -- If operator matches formals, record its name on the call. -- If the operator is overloaded, Resolve will select the -- correct one from the list of interpretations. The call -- node itself carries the first candidate. Set_Entity (Name (N), Nam); Success := True; elsif Report and then Etype (N) = Any_Type then Error_Msg_N ("incompatible arguments for operator", N); end if; else -- Normalize_Actuals has chained the named associations in the -- correct order of the formals. Actual := First_Actual (N); Formal := First_Formal (Nam); First_Form := Formal; -- If we are analyzing a call rewritten from object notation, skip -- first actual, which may be rewritten later as an explicit -- dereference. if Must_Skip then Next_Actual (Actual); Next_Formal (Formal); end if; while Present (Actual) and then Present (Formal) loop if Nkind (Parent (Actual)) /= N_Parameter_Association or else Chars (Selector_Name (Parent (Actual))) = Chars (Formal) then -- The actual can be compatible with the formal, but we must -- also check that the context is not an address type that is -- visibly an integer type. In this case the use of literals is -- illegal, except in the body of descendants of system, where -- arithmetic operations on address are of course used. if Has_Compatible_Type (Actual, Etype (Formal)) and then (Etype (Actual) /= Universal_Integer or else not Is_Descendant_Of_Address (Etype (Formal)) or else In_Predefined_Unit (N)) then Next_Actual (Actual); Next_Formal (Formal); -- In Allow_Integer_Address mode, we allow an actual integer to -- match a formal address type and vice versa. We only do this -- if we are certain that an error will otherwise be issued elsif Address_Integer_Convert_OK (Etype (Actual), Etype (Formal)) and then (Report and not Is_Indexed and not Is_Indirect) then -- Handle this case by introducing an unchecked conversion Rewrite (Actual, Unchecked_Convert_To (Etype (Formal), Relocate_Node (Actual))); Analyze_And_Resolve (Actual, Etype (Formal)); Next_Actual (Actual); Next_Formal (Formal); -- Under relaxed RM semantics silently replace occurrences of -- null by System.Address_Null. We only do this if we know that -- an error will otherwise be issued. elsif Null_To_Null_Address_Convert_OK (Actual, Etype (Formal)) and then (Report and not Is_Indexed and not Is_Indirect) then Replace_Null_By_Null_Address (Actual); Analyze_And_Resolve (Actual, Etype (Formal)); Next_Actual (Actual); Next_Formal (Formal); elsif Compatible_Types_In_Predicate (Etype (Formal), Etype (Actual)) then Next_Actual (Actual); Next_Formal (Formal); -- A current instance used as an actual of a function, -- whose body has not been seen, may include a formal -- whose type is an incomplete view of an enclosing -- type declaration containing the current call (e.g. -- in the Expression for a component declaration). -- In this case, update the signature of the subprogram -- so the formal has the type of the full view. elsif Inside_Init_Proc and then Nkind (Actual) = N_Identifier and then Ekind (Etype (Formal)) = E_Incomplete_Type and then Etype (Actual) = Full_View (Etype (Formal)) then Set_Etype (Formal, Etype (Actual)); Next_Actual (Actual); Next_Formal (Formal); -- Generate a class-wide type conversion for instances of -- class-wide equivalent types to their corresponding -- mutably tagged type. elsif Is_Mutably_Tagged_CW_Equivalent_Type (Etype (Actual)) and then Etype (Formal) = Parent_Subtype (Etype (Actual)) then Make_Mutably_Tagged_Conversion (Actual); Next_Actual (Actual); Next_Formal (Formal); -- Handle failed type check else if Debug_Flag_E then Write_Str (" type checking fails in call "); Write_Int (Int (N)); Write_Str (" with formal "); Write_Int (Int (Formal)); Write_Str (" in subprogram "); Write_Int (Int (Nam)); Write_Eol; end if; -- Comment needed on the following test??? if Report and not Is_Indexed and not Is_Indirect then -- Ada 2005 (AI-251): Complete the error notification -- to help new Ada 2005 users. if Is_Class_Wide_Type (Etype (Formal)) and then Is_Interface (Etype (Etype (Formal))) and then not Interface_Present_In_Ancestor (Typ => Etype (Actual), Iface => Etype (Etype (Formal))) then Error_Msg_NE ("(Ada 2005) does not implement interface }", Actual, Etype (Etype (Formal))); end if; -- If we are going to output a secondary error message -- below, we need to have Wrong_Type output the main one. Wrong_Type (Actual, Etype (Formal), Multiple => All_Errors_Mode); if Nkind (Actual) = N_Op_Eq and then Nkind (Left_Opnd (Actual)) = N_Identifier then Formal := First_Formal (Nam); while Present (Formal) loop if Chars (Left_Opnd (Actual)) = Chars (Formal) then Error_Msg_N -- CODEFIX ("possible misspelling of `='>`!", Actual); exit; end if; Next_Formal (Formal); end loop; end if; if All_Errors_Mode then Error_Msg_Sloc := Sloc (Nam); if Etype (Formal) = Any_Type then Error_Msg_N ("there is no legal actual parameter", Actual); end if; if Is_Overloadable (Nam) and then Present (Alias (Nam)) and then not Comes_From_Source (Nam) then Error_Msg_NE ("\\ =='> in call to inherited operation & #!", Actual, Nam); elsif Ekind (Nam) = E_Subprogram_Type then declare Access_To_Subprogram_Typ : constant Entity_Id := Defining_Identifier (Associated_Node_For_Itype (Nam)); begin Error_Msg_NE ("\\ =='> in call to dereference of &#!", Actual, Access_To_Subprogram_Typ); end; else Error_Msg_NE ("\\ =='> in call to &#!", Actual, Nam); end if; end if; end if; return; end if; else -- Normalize_Actuals has verified that a default value exists -- for this formal. Current actual names a subsequent formal. Next_Formal (Formal); end if; end loop; -- Due to our current model of controlled type expansion we may -- have resolved a user call to a non-visible controlled primitive -- since these inherited subprograms may be generated in the current -- scope. This is a side effect of the need for the expander to be -- able to resolve internally generated calls. -- Specifically, the issue appears when predefined controlled -- operations get called on a type extension whose parent is a -- private extension completed with a controlled extension - see -- below: -- package X is -- type Par_Typ is tagged private; -- private -- type Par_Typ is new Controlled with null record; -- end; -- ... -- procedure Main is -- type Ext_Typ is new Par_Typ with null record; -- Obj : Ext_Typ; -- begin -- Finalize (Obj); -- Will improperly resolve -- end; -- To avoid breaking privacy, Is_Hidden gets set elsewhere on such -- primitives, but we still need to verify that Nam is indeed a -- non-visible controlled subprogram. So, we do that here and issue -- the appropriate error. if Is_Hidden (Nam) and then not In_Instance and then not Comes_From_Source (Nam) and then Comes_From_Source (N) -- Verify Nam is a non-visible controlled primitive and then Chars (Nam) in Name_Adjust | Name_Finalize | Name_Initialize and then Ekind (Nam) = E_Procedure and then Is_Controlled (Etype (First_Form)) and then No (Next_Formal (First_Form)) and then not Is_Visibly_Controlled (Etype (First_Form)) then Error_Msg_Node_2 := Etype (First_Form); Error_Msg_NE ("call to non-visible controlled primitive & on type" & " &", N, Nam); end if; -- On exit, all actuals match Indicate_Name_And_Type; end if; end Analyze_One_Call; --------------------------- -- Analyze_Operator_Call -- --------------------------- procedure Analyze_Operator_Call (N : Node_Id; Op_Id : Entity_Id) is Op_Name : constant Name_Id := Chars (Op_Id); Act1 : constant Node_Id := First_Actual (N); Act2 : constant Node_Id := Next_Actual (Act1); begin -- Binary operator case if Present (Act2) then -- If more than two operands, then not binary operator after all if Present (Next_Actual (Act2)) then return; end if; -- Otherwise action depends on operator case Op_Name is when Name_Op_Add | Name_Op_Divide | Name_Op_Expon | Name_Op_Mod | Name_Op_Multiply | Name_Op_Rem | Name_Op_Subtract => Find_Arithmetic_Types (Act1, Act2, Op_Id, N); when Name_Op_And | Name_Op_Or | Name_Op_Xor => Find_Boolean_Types (Act1, Act2, Op_Id, N); when Name_Op_Eq | Name_Op_Ge | Name_Op_Gt | Name_Op_Le | Name_Op_Lt | Name_Op_Ne => Find_Comparison_Equality_Types (Act1, Act2, Op_Id, N); when Name_Op_Concat => Find_Concatenation_Types (Act1, Act2, Op_Id, N); -- Is this when others, or should it be an abort??? when others => null; end case; -- Unary operator case else case Op_Name is when Name_Op_Abs | Name_Op_Add | Name_Op_Subtract => Find_Unary_Types (Act1, Op_Id, N); when Name_Op_Not => Find_Negation_Types (Act1, Op_Id, N); -- Is this when others correct, or should it be an abort??? when others => null; end case; end if; end Analyze_Operator_Call; ------------------------------------------- -- Analyze_Overloaded_Selected_Component -- ------------------------------------------- procedure Analyze_Overloaded_Selected_Component (N : Node_Id) is Nam : constant Node_Id := Prefix (N); Sel : constant Node_Id := Selector_Name (N); Comp : Entity_Id; I : Interp_Index; It : Interp; T : Entity_Id; begin Set_Etype (Sel, Any_Type); Get_First_Interp (Nam, I, It); while Present (It.Typ) loop if Is_Access_Type (It.Typ) then T := Designated_Type (It.Typ); Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); else T := It.Typ; end if; -- Locate the component. For a private prefix the selector can denote -- a discriminant. if Is_Record_Type (T) or else Is_Private_Type (T) then -- If the prefix is a class-wide type, the visible components are -- those of the base type. if Is_Class_Wide_Type (T) then T := Etype (T); end if; Comp := First_Entity (T); while Present (Comp) loop if Chars (Comp) = Chars (Sel) and then Is_Visible_Component (Comp, Sel) then -- AI05-105: if the context is an object renaming with -- an anonymous access type, the expected type of the -- object must be anonymous. This is a name resolution rule. if Nkind (Parent (N)) /= N_Object_Renaming_Declaration or else No (Access_Definition (Parent (N))) or else Is_Anonymous_Access_Type (Etype (Comp)) then Set_Entity (Sel, Comp); Set_Etype (Sel, Etype (Comp)); Add_One_Interp (N, Etype (Comp), Etype (Comp)); Check_Implicit_Dereference (N, Etype (Comp)); -- This also specifies a candidate to resolve the name. -- Further overloading will be resolved from context. -- The selector name itself does not carry overloading -- information. Set_Etype (Nam, It.Typ); else -- Named access type in the context of a renaming -- declaration with an access definition. Remove -- inapplicable candidate. Remove_Interp (I); end if; end if; Next_Entity (Comp); end loop; elsif Is_Concurrent_Type (T) then Comp := First_Entity (T); while Present (Comp) and then Comp /= First_Private_Entity (T) loop if Chars (Comp) = Chars (Sel) then if Is_Overloadable (Comp) then Add_One_Interp (Sel, Comp, Etype (Comp)); else Set_Entity_With_Checks (Sel, Comp); Generate_Reference (Comp, Sel); end if; Set_Etype (Sel, Etype (Comp)); Set_Etype (N, Etype (Comp)); Set_Etype (Nam, It.Typ); end if; Next_Entity (Comp); end loop; Set_Is_Overloaded (N, Is_Overloaded (Sel)); end if; Get_Next_Interp (I, It); end loop; if Etype (N) = Any_Type and then not Try_Object_Operation (N) then Error_Msg_NE ("undefined selector& for overloaded prefix", N, Sel); Set_Entity (Sel, Any_Id); Set_Etype (Sel, Any_Type); end if; end Analyze_Overloaded_Selected_Component; ---------------------------------- -- Analyze_Qualified_Expression -- ---------------------------------- procedure Analyze_Qualified_Expression (N : Node_Id) is Expr : constant Node_Id := Expression (N); Mark : constant Entity_Id := Subtype_Mark (N); I : Interp_Index; It : Interp; T : Entity_Id; begin Find_Type (Mark); T := Entity (Mark); if Nkind (Enclosing_Declaration (N)) in N_Formal_Type_Declaration | N_Full_Type_Declaration | N_Incomplete_Type_Declaration | N_Protected_Type_Declaration | N_Private_Extension_Declaration | N_Private_Type_Declaration | N_Subtype_Declaration | N_Task_Type_Declaration and then T = Defining_Identifier (Enclosing_Declaration (N)) then Error_Msg_N ("current instance not allowed", Mark); T := Any_Type; end if; Set_Etype (N, T); Analyze_Expression (Expr); if T = Any_Type then return; end if; Check_Fully_Declared (T, N); -- If expected type is class-wide, check for exact match before -- expansion, because if the expression is a dispatching call it -- may be rewritten as explicit dereference with class-wide result. -- If expression is overloaded, retain only interpretations that -- will yield exact matches. if Is_Class_Wide_Type (T) then if not Is_Overloaded (Expr) then if Base_Type (Etype (Expr)) /= Base_Type (T) and then Etype (Expr) /= Raise_Type then if Nkind (Expr) = N_Aggregate then Error_Msg_N ("type of aggregate cannot be class-wide", Expr); else Wrong_Type (Expr, T); end if; end if; else Get_First_Interp (Expr, I, It); while Present (It.Nam) loop if Base_Type (It.Typ) /= Base_Type (T) then Remove_Interp (I); end if; Get_Next_Interp (I, It); end loop; end if; end if; end Analyze_Qualified_Expression; ----------------------------------- -- Analyze_Quantified_Expression -- ----------------------------------- procedure Analyze_Quantified_Expression (N : Node_Id) is function Is_Empty_Range (Typ : Entity_Id) return Boolean; -- Return True if the iterator is part of a quantified expression and -- the range is known to be statically empty. function No_Else_Or_Trivial_True (If_Expr : Node_Id) return Boolean; -- Determine whether if expression If_Expr lacks an else part or if it -- has one, it evaluates to True. -------------------- -- Is_Empty_Range -- -------------------- function Is_Empty_Range (Typ : Entity_Id) return Boolean is begin return Is_Array_Type (Typ) and then Compile_Time_Known_Bounds (Typ) and then Expr_Value (Type_Low_Bound (Etype (First_Index (Typ)))) > Expr_Value (Type_High_Bound (Etype (First_Index (Typ)))); end Is_Empty_Range; ----------------------------- -- No_Else_Or_Trivial_True -- ----------------------------- function No_Else_Or_Trivial_True (If_Expr : Node_Id) return Boolean is Else_Expr : constant Node_Id := Next (Next (First (Expressions (If_Expr)))); begin return No (Else_Expr) or else (Compile_Time_Known_Value (Else_Expr) and then Is_True (Expr_Value (Else_Expr))); end No_Else_Or_Trivial_True; -- Local variables Cond : constant Node_Id := Condition (N); Loc : constant Source_Ptr := Sloc (N); Loop_Id : Entity_Id; QE_Scop : Entity_Id; -- Start of processing for Analyze_Quantified_Expression begin -- Create a scope to emulate the loop-like behavior of the quantified -- expression. The scope is needed to provide proper visibility of the -- loop variable. QE_Scop := New_Internal_Entity (E_Loop, Current_Scope, Loc, 'L'); Set_Etype (QE_Scop, Standard_Void_Type); Set_Scope (QE_Scop, Current_Scope); Set_Parent (QE_Scop, N); Push_Scope (QE_Scop); -- All constituents are preanalyzed and resolved to avoid untimely -- generation of various temporaries and types. Full analysis and -- expansion is carried out when the quantified expression is -- transformed into an expression with actions. if Present (Iterator_Specification (N)) then Preanalyze (Iterator_Specification (N)); -- Do not proceed with the analysis when the range of iteration is -- empty. if Is_Entity_Name (Name (Iterator_Specification (N))) and then Is_Empty_Range (Etype (Name (Iterator_Specification (N)))) then Preanalyze_And_Resolve (Condition (N), Standard_Boolean); End_Scope; -- Emit a warning and replace expression with its static value if All_Present (N) then Error_Msg_N ("??quantified expression with ALL " & "over a null range has value True", N); Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); else Error_Msg_N ("??quantified expression with SOME " & "over a null range has value False", N); Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); end if; Analyze (N); return; end if; else pragma Assert (Present (Loop_Parameter_Specification (N))); declare Loop_Par : constant Node_Id := Loop_Parameter_Specification (N); begin Preanalyze (Loop_Par); if Nkind (Discrete_Subtype_Definition (Loop_Par)) = N_Function_Call and then Parent (Loop_Par) /= N then -- The parser cannot distinguish between a loop specification -- and an iterator specification. If after preanalysis the -- proper form has been recognized, rewrite the expression to -- reflect the right kind. This is needed for proper ASIS -- navigation. If expansion is enabled, the transformation is -- performed when the expression is rewritten as a loop. -- Is this still needed??? Set_Iterator_Specification (N, New_Copy_Tree (Iterator_Specification (Parent (Loop_Par)))); Set_Defining_Identifier (Iterator_Specification (N), Relocate_Node (Defining_Identifier (Loop_Par))); Set_Name (Iterator_Specification (N), Relocate_Node (Discrete_Subtype_Definition (Loop_Par))); Set_Comes_From_Source (Iterator_Specification (N), Comes_From_Source (Loop_Parameter_Specification (N))); Set_Loop_Parameter_Specification (N, Empty); end if; end; end if; Preanalyze_And_Resolve (Cond, Standard_Boolean); End_Scope; Set_Etype (N, Standard_Boolean); -- Verify that the loop variable is used within the condition of the -- quantified expression. if Present (Iterator_Specification (N)) then Loop_Id := Defining_Identifier (Iterator_Specification (N)); else Loop_Id := Defining_Identifier (Loop_Parameter_Specification (N)); end if; declare type Subexpr_Kind is (Full, Conjunct, Disjunct); procedure Check_Subexpr (Expr : Node_Id; Kind : Subexpr_Kind); -- Check that the quantified variable appears in every sub-expression -- of the quantified expression. If Kind is Full, Expr is the full -- expression. If Kind is Conjunct (resp. Disjunct), Expr is a -- conjunct (resp. disjunct) of the full expression. ------------------- -- Check_Subexpr -- ------------------- procedure Check_Subexpr (Expr : Node_Id; Kind : Subexpr_Kind) is begin if Nkind (Expr) in N_Op_And | N_And_Then and then Kind /= Disjunct then Check_Subexpr (Left_Opnd (Expr), Conjunct); Check_Subexpr (Right_Opnd (Expr), Conjunct); elsif Nkind (Expr) in N_Op_Or | N_Or_Else and then Kind /= Conjunct then Check_Subexpr (Left_Opnd (Expr), Disjunct); Check_Subexpr (Right_Opnd (Expr), Disjunct); elsif Kind /= Full and then not Referenced (Loop_Id, Expr) then declare Sub : constant String := (if Kind = Conjunct then "conjunct" else "disjunct"); begin Error_Msg_NE ("?.t?unused variable & in " & Sub, Expr, Loop_Id); Error_Msg_NE ("\consider extracting " & Sub & " from quantified " & "expression", Expr, Loop_Id); end; end if; end Check_Subexpr; begin if Warn_On_Suspicious_Contract and then not Is_Internal_Name (Chars (Loop_Id)) then if not Referenced (Loop_Id, Cond) then Error_Msg_N ("?.t?unused variable &", Loop_Id); else Check_Subexpr (Cond, Kind => Full); end if; end if; end; -- Diagnose a possible misuse of the SOME existential quantifier. When -- we have a quantified expression of the form: -- for some X => (if P then Q [else True]) -- any value for X that makes P False results in the if expression being -- trivially True, and so also results in the quantified expression -- being trivially True. if Warn_On_Suspicious_Contract and then not All_Present (N) and then Nkind (Cond) = N_If_Expression and then No_Else_Or_Trivial_True (Cond) then Error_Msg_N ("?.t?suspicious expression", N); Error_Msg_N ("\\did you mean (for all X ='> (if P then Q))", N); Error_Msg_N ("\\or (for some X ='> P and then Q) instead'?", N); end if; end Analyze_Quantified_Expression; ------------------- -- Analyze_Range -- ------------------- procedure Analyze_Range (N : Node_Id) is L : constant Node_Id := Low_Bound (N); H : constant Node_Id := High_Bound (N); I1, I2 : Interp_Index; It1, It2 : Interp; procedure Check_Common_Type (T1, T2 : Entity_Id); -- Verify the compatibility of two types, and choose the -- non universal one if the other is universal. procedure Check_High_Bound (T : Entity_Id); -- Test one interpretation of the low bound against all those -- of the high bound. procedure Check_Universal_Expression (N : Node_Id); -- In Ada 83, reject bounds of a universal range that are not literals -- or entity names. ----------------------- -- Check_Common_Type -- ----------------------- procedure Check_Common_Type (T1, T2 : Entity_Id) is begin if Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1) then if Is_Universal_Numeric_Type (T1) or else T1 = Any_Character then Add_One_Interp (N, Base_Type (T2), Base_Type (T2)); elsif T1 = T2 then Add_One_Interp (N, T1, T1); else Add_One_Interp (N, Base_Type (T1), Base_Type (T1)); end if; end if; end Check_Common_Type; ---------------------- -- Check_High_Bound -- ---------------------- procedure Check_High_Bound (T : Entity_Id) is begin if not Is_Overloaded (H) then Check_Common_Type (T, Etype (H)); else Get_First_Interp (H, I2, It2); while Present (It2.Typ) loop Check_Common_Type (T, It2.Typ); Get_Next_Interp (I2, It2); end loop; end if; end Check_High_Bound; -------------------------------- -- Check_Universal_Expression -- -------------------------------- procedure Check_Universal_Expression (N : Node_Id) is begin if Etype (N) = Universal_Integer and then Nkind (N) /= N_Integer_Literal and then not Is_Entity_Name (N) and then Nkind (N) /= N_Attribute_Reference then Error_Msg_N ("illegal bound in discrete range", N); end if; end Check_Universal_Expression; -- Start of processing for Analyze_Range begin Set_Etype (N, Any_Type); Analyze_Expression (L); Analyze_Expression (H); if Etype (L) = Any_Type or else Etype (H) = Any_Type then return; else if not Is_Overloaded (L) then Check_High_Bound (Etype (L)); else Get_First_Interp (L, I1, It1); while Present (It1.Typ) loop Check_High_Bound (It1.Typ); Get_Next_Interp (I1, It1); end loop; end if; -- If result is Any_Type, then we did not find a compatible pair if Etype (N) = Any_Type then Error_Msg_N ("incompatible types in range", N); end if; end if; if Ada_Version = Ada_83 and then (Nkind (Parent (N)) = N_Loop_Parameter_Specification or else Nkind (Parent (N)) = N_Constrained_Array_Definition) then Check_Universal_Expression (L); Check_Universal_Expression (H); end if; Check_Function_Writable_Actuals (N); end Analyze_Range; ----------------------- -- Analyze_Reference -- ----------------------- procedure Analyze_Reference (N : Node_Id) is P : constant Node_Id := Prefix (N); E : Entity_Id; T : Entity_Id; Acc_Type : Entity_Id; begin Analyze (P); -- An interesting error check, if we take the 'Ref of an object for -- which a pragma Atomic or Volatile has been given, and the type of the -- object is not Atomic or Volatile, then we are in trouble. The problem -- is that no trace of the atomic/volatile status will remain for the -- backend to respect when it deals with the resulting pointer, since -- the pointer type will not be marked atomic (it is a pointer to the -- base type of the object). -- It is not clear if that can ever occur, but in case it does, we will -- generate an error message. Not clear if this message can ever be -- generated, and pretty clear that it represents a bug if it is, still -- seems worth checking, except in CodePeer mode where we do not really -- care and don't want to bother the user. T := Etype (P); if Is_Entity_Name (P) and then Is_Object_Reference (P) and then not CodePeer_Mode then E := Entity (P); T := Etype (P); if (Has_Atomic_Components (E) and then not Has_Atomic_Components (T)) or else (Has_Volatile_Components (E) and then not Has_Volatile_Components (T)) or else (Is_Atomic (E) and then not Is_Atomic (T)) or else (Is_Volatile (E) and then not Is_Volatile (T)) then Error_Msg_N ("cannot take reference to Atomic/Volatile object", N); end if; end if; -- Carry on with normal processing Acc_Type := Create_Itype (E_Allocator_Type, N); Set_Etype (Acc_Type, Acc_Type); Set_Directly_Designated_Type (Acc_Type, Etype (P)); Set_Etype (N, Acc_Type); end Analyze_Reference; -------------------------------- -- Analyze_Selected_Component -- -------------------------------- -- Prefix is a record type or a task or protected type. In the latter case, -- the selector must denote a visible entry. procedure Analyze_Selected_Component (N : Node_Id) is Pref : constant Node_Id := Prefix (N); Sel : constant Node_Id := Selector_Name (N); Act_Decl : Node_Id; Comp : Entity_Id := Empty; Has_Candidate : Boolean := False; Hidden_Comp : Entity_Id; In_Scope : Boolean; Is_Private_Op : Boolean; Parent_N : Node_Id; Prefix_Type : Entity_Id; Type_To_Use : Entity_Id; -- In most cases this is the Prefix_Type, but if the Prefix_Type is -- a class-wide type, we use its root type, whose components are -- present in the class-wide type. Is_Single_Concurrent_Object : Boolean; -- Set True if the prefix is a single task or a single protected object function Constraint_Has_Unprefixed_Discriminant_Reference (Typ : Entity_Id) return Boolean; -- Given a subtype that is subject to a discriminant-dependent -- constraint, returns True if any of the values of the constraint -- (i.e., any of the index values for an index constraint, any of -- the discriminant values for a discriminant constraint) -- are unprefixed discriminant names. function Has_Mode_Conformant_Spec (Comp : Entity_Id) return Boolean; -- It is known that the parent of N denotes a subprogram call. Comp -- is an overloadable component of the concurrent type of the prefix. -- Determine whether all formals of the parent of N and Comp are mode -- conformant. If the parent node is not analyzed yet it may be an -- indexed component rather than a function call. function Has_Dereference (Nod : Node_Id) return Boolean; -- Check whether Nod includes a dereference, explicit or implicit, at -- any recursive level. function Is_Simple_Indexed_Component (Nod : Node_Id) return Boolean; -- Check whether Nod is a simple indexed component in the context function Try_By_Protected_Procedure_Prefixed_View return Boolean; -- Return True if N is an access attribute whose prefix is a prefixed -- class-wide (synchronized or protected) interface view for which some -- interpretation is a procedure with synchronization kind By_Protected -- _Procedure, and collect all its interpretations (since it may be an -- overloaded interface primitive); otherwise return False. function Try_Selected_Component_In_Instance (Typ : Entity_Id) return Boolean; -- If Typ is the actual for a formal derived type, or a derived type -- thereof, the component inherited from the generic parent may not -- be visible in the actual, but the selected component is legal. Climb -- up the derivation chain of the generic parent type and return True if -- we find the proper ancestor type; otherwise return False. ------------------------------------------------------ -- Constraint_Has_Unprefixed_Discriminant_Reference -- ------------------------------------------------------ function Constraint_Has_Unprefixed_Discriminant_Reference (Typ : Entity_Id) return Boolean is function Is_Discriminant_Name (N : Node_Id) return Boolean is (Nkind (N) = N_Identifier and then Ekind (Entity (N)) = E_Discriminant); begin if Is_Array_Type (Typ) then declare Index : Node_Id := First_Index (Typ); Rng : Node_Id; begin while Present (Index) loop Rng := Index; if Nkind (Rng) = N_Subtype_Indication then Rng := Range_Expression (Constraint (Rng)); end if; if Nkind (Rng) = N_Range then if Is_Discriminant_Name (Low_Bound (Rng)) or else Is_Discriminant_Name (High_Bound (Rng)) then return True; end if; end if; Next_Index (Index); end loop; end; else declare Elmt : Elmt_Id := First_Elmt (Discriminant_Constraint (Typ)); begin while Present (Elmt) loop if Is_Discriminant_Name (Node (Elmt)) then return True; end if; Next_Elmt (Elmt); end loop; end; end if; return False; end Constraint_Has_Unprefixed_Discriminant_Reference; ------------------------------ -- Has_Mode_Conformant_Spec -- ------------------------------ function Has_Mode_Conformant_Spec (Comp : Entity_Id) return Boolean is Comp_Param : Entity_Id; Param : Node_Id; Param_Typ : Entity_Id; begin Comp_Param := First_Formal (Comp); if Nkind (Parent (N)) = N_Indexed_Component then Param := First (Expressions (Parent (N))); else Param := First (Parameter_Associations (Parent (N))); end if; while Present (Comp_Param) and then Present (Param) loop Param_Typ := Find_Parameter_Type (Param); if Present (Param_Typ) and then not Conforming_Types (Etype (Comp_Param), Param_Typ, Mode_Conformant) then return False; end if; Next_Formal (Comp_Param); Next (Param); end loop; -- One of the specs has additional formals; there is no match, unless -- this may be an indexing of a parameterless call. -- Note that when expansion is disabled, the corresponding record -- type of synchronized types is not constructed, so that there is -- no point is attempting an interpretation as a prefixed call, as -- this is bound to fail because the primitive operations will not -- be properly located. if Present (Comp_Param) or else Present (Param) then if Needs_No_Actuals (Comp) and then Is_Array_Type (Etype (Comp)) and then not Expander_Active then return True; else return False; end if; end if; return True; end Has_Mode_Conformant_Spec; --------------------- -- Has_Dereference -- --------------------- function Has_Dereference (Nod : Node_Id) return Boolean is begin if Nkind (Nod) = N_Explicit_Dereference then return True; elsif Is_Access_Type (Etype (Nod)) then return True; elsif Nkind (Nod) in N_Indexed_Component | N_Selected_Component then return Has_Dereference (Prefix (Nod)); else return False; end if; end Has_Dereference; --------------------------------- -- Is_Simple_Indexed_Component -- --------------------------------- function Is_Simple_Indexed_Component (Nod : Node_Id) return Boolean is Expr : Node_Id; begin -- Nod must be an indexed component if Nkind (Nod) /= N_Indexed_Component then return False; end if; -- The context must not be a nested selected component if Nkind (Pref) = N_Selected_Component then return False; end if; -- The expressions must not be case expressions Expr := First (Expressions (Nod)); while Present (Expr) loop if Nkind (Expr) = N_Case_Expression then return False; end if; Next (Expr); end loop; return True; end Is_Simple_Indexed_Component; ---------------------------------------------- -- Try_By_Protected_Procedure_Prefixed_View -- ---------------------------------------------- function Try_By_Protected_Procedure_Prefixed_View return Boolean is Candidate : Node_Id := Empty; Elmt : Elmt_Id; Prim : Node_Id; begin if Nkind (Parent (N)) = N_Attribute_Reference and then Attribute_Name (Parent (N)) in Name_Access | Name_Unchecked_Access | Name_Unrestricted_Access and then Is_Class_Wide_Type (Prefix_Type) and then (Is_Synchronized_Interface (Prefix_Type) or else Is_Protected_Interface (Prefix_Type)) then -- If we have not found yet any interpretation then mark this -- one as the first interpretation (cf. Add_One_Interp). if No (Etype (Sel)) then Set_Etype (Sel, Any_Type); end if; Elmt := First_Elmt (Primitive_Operations (Etype (Prefix_Type))); while Present (Elmt) loop Prim := Node (Elmt); if Chars (Prim) = Chars (Sel) and then Is_By_Protected_Procedure (Prim) then Candidate := New_Copy (Prim); -- Skip the controlling formal; required to check type -- conformance of the target access to protected type -- (see Conforming_Types). Set_First_Entity (Candidate, Next_Entity (First_Entity (Prim))); Add_One_Interp (Sel, Candidate, Etype (Prim)); Set_Etype (N, Etype (Prim)); end if; Next_Elmt (Elmt); end loop; end if; -- Propagate overloaded attribute if Present (Candidate) and then Is_Overloaded (Sel) then Set_Is_Overloaded (N); end if; return Present (Candidate); end Try_By_Protected_Procedure_Prefixed_View; ---------------------------------------- -- Try_Selected_Component_In_Instance -- ---------------------------------------- function Try_Selected_Component_In_Instance (Typ : Entity_Id) return Boolean is procedure Find_Component_In_Instance (Rec : Entity_Id); -- In an instance, a component of a private extension may not be -- visible while it was visible in the generic. Search candidate -- scope for a component with the proper identifier. If a match is -- found, the Etype of both N and Sel are set from this component, -- and the entity of Sel is set to reference this component. If no -- match is found, Entity (Sel) remains unset. For a derived type -- that is an actual of the instance, the desired component may be -- found in any ancestor. -------------------------------- -- Find_Component_In_Instance -- -------------------------------- procedure Find_Component_In_Instance (Rec : Entity_Id) is Comp : Entity_Id; Typ : Entity_Id; begin Typ := Rec; while Present (Typ) loop Comp := First_Component (Typ); while Present (Comp) loop if Chars (Comp) = Chars (Sel) then Set_Entity_With_Checks (Sel, Comp); Set_Etype (Sel, Etype (Comp)); Set_Etype (N, Etype (Comp)); return; end if; Next_Component (Comp); end loop; -- If not found, the component may be declared in the parent -- type or its full view, if any. if Is_Derived_Type (Typ) then Typ := Etype (Typ); if Is_Private_Type (Typ) then Typ := Full_View (Typ); end if; else return; end if; end loop; -- If we fall through, no match, so no changes made return; end Find_Component_In_Instance; -- Local variables Par : Entity_Id; -- Start of processing for Try_Selected_Component_In_Instance begin pragma Assert (In_Instance and then Is_Tagged_Type (Typ)); pragma Assert (Etype (N) = Any_Type); -- Climb up derivation chain to generic actual subtype Par := Typ; while not Is_Generic_Actual_Type (Par) loop if Ekind (Par) = E_Record_Type then Par := Parent_Subtype (Par); exit when No (Par); else exit when Par = Etype (Par); Par := Etype (Par); end if; end loop; -- Another special case: the type is an extension of a private -- type T, either is an actual in an instance or is immediately -- visible, and we are in the body of the instance, which means -- the generic body had a full view of the type declaration for -- T or some ancestor that defines the component in question. -- This happens because Is_Visible_Component returned False on -- this component, as T or the ancestor is still private since -- the Has_Private_View mechanism is bypassed because T or the -- ancestor is not directly referenced in the generic body. if Is_Derived_Type (Typ) and then (Used_As_Generic_Actual (Base_Type (Typ)) or else Is_Immediately_Visible (Typ)) and then In_Instance_Body and then Present (Parent_Subtype (Typ)) then Find_Component_In_Instance (Parent_Subtype (Typ)); -- If Par is a generic actual, look for component in ancestor types. -- Skip this if we have no Declaration_Node, as is the case for -- itypes. elsif Present (Par) and then Is_Generic_Actual_Type (Par) and then Present (Declaration_Node (Par)) then Par := Generic_Parent_Type (Declaration_Node (Par)); loop Find_Component_In_Instance (Par); exit when Present (Entity (Sel)) or else Par = Etype (Par); Par := Etype (Par); end loop; end if; return Etype (N) /= Any_Type; end Try_Selected_Component_In_Instance; -- Start of processing for Analyze_Selected_Component begin Set_Etype (N, Any_Type); if Is_Overloaded (Pref) then Analyze_Overloaded_Selected_Component (N); return; elsif Etype (Pref) = Any_Type then Set_Entity (Sel, Any_Id); Set_Etype (Sel, Any_Type); return; else Prefix_Type := Etype (Pref); end if; if Is_Access_Type (Prefix_Type) then -- A RACW object can never be used as prefix of a selected component -- since that means it is dereferenced without being a controlling -- operand of a dispatching operation (RM E.2.2(16/1)). Before -- reporting an error, we must check whether this is actually a -- dispatching call in prefix form. if Is_Remote_Access_To_Class_Wide_Type (Prefix_Type) and then Comes_From_Source (N) then if Try_Object_Operation (N) then return; else Error_Msg_N ("invalid dereference of a remote access-to-class-wide value", N); end if; -- Normal case of selected component applied to access type else Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); Prefix_Type := Implicitly_Designated_Type (Prefix_Type); end if; -- Handle mutably tagged types elsif Is_Class_Wide_Equivalent_Type (Prefix_Type) then Prefix_Type := Parent_Subtype (Prefix_Type); -- If we have an explicit dereference of a remote access-to-class-wide -- value, then issue an error (see RM-E.2.2(16/1)). However we first -- have to check for the case of a prefix that is a controlling operand -- of a prefixed dispatching call, as the dereference is legal in that -- case. Normally this condition is checked in Validate_Remote_Access_ -- To_Class_Wide_Type, but we have to defer the checking for selected -- component prefixes because of the prefixed dispatching call case. -- Note that implicit dereferences are checked for this just above. elsif Nkind (Pref) = N_Explicit_Dereference and then Is_Remote_Access_To_Class_Wide_Type (Etype (Prefix (Pref))) and then Comes_From_Source (N) then if Try_Object_Operation (N) then return; else Error_Msg_N ("invalid dereference of a remote access-to-class-wide value", N); end if; end if; -- (Ada 2005): if the prefix is the limited view of a type, and -- the context already includes the full view, use the full view -- in what follows, either to retrieve a component of to find -- a primitive operation. If the prefix is an explicit dereference, -- set the type of the prefix to reflect this transformation. -- If the nonlimited view is itself an incomplete type, get the -- full view if available. if From_Limited_With (Prefix_Type) and then Has_Non_Limited_View (Prefix_Type) then Prefix_Type := Get_Full_View (Non_Limited_View (Prefix_Type)); if Nkind (N) = N_Explicit_Dereference then Set_Etype (Prefix (N), Prefix_Type); end if; end if; if Ekind (Prefix_Type) = E_Private_Subtype then Prefix_Type := Base_Type (Prefix_Type); end if; Type_To_Use := Prefix_Type; -- For class-wide types, use the entity list of the root type. This -- indirection is specially important for private extensions because -- only the root type get switched (not the class-wide type). if Is_Class_Wide_Type (Prefix_Type) then Type_To_Use := Root_Type (Prefix_Type); end if; -- If the prefix is a single concurrent object, use its name in error -- messages, rather than that of its anonymous type. Is_Single_Concurrent_Object := Is_Concurrent_Type (Prefix_Type) and then Is_Internal_Name (Chars (Prefix_Type)) and then not Is_Derived_Type (Prefix_Type) and then Is_Entity_Name (Pref); -- Avoid initializing Comp if that initialization is not needed -- (and, more importantly, if the call to First_Entity could fail). if Has_Discriminants (Type_To_Use) or else Is_Record_Type (Type_To_Use) or else Is_Private_Type (Type_To_Use) or else Is_Concurrent_Type (Type_To_Use) then Comp := First_Entity (Type_To_Use); end if; -- If the selector has an original discriminant, the node appears in -- an instance. Replace the discriminant with the corresponding one -- in the current discriminated type. For nested generics, this must -- be done transitively, so note the new original discriminant. if Nkind (Sel) = N_Identifier and then In_Instance and then Present (Original_Discriminant (Sel)) then Comp := Find_Corresponding_Discriminant (Sel, Prefix_Type); -- Mark entity before rewriting, for completeness and because -- subsequent semantic checks might examine the original node. Set_Entity (Sel, Comp); Rewrite (Sel, New_Occurrence_Of (Comp, Sloc (N))); Set_Original_Discriminant (Sel, Comp); Set_Etype (N, Etype (Comp)); Check_Implicit_Dereference (N, Etype (Comp)); elsif Is_Record_Type (Prefix_Type) then -- Find a component with the given name. If the node is a prefixed -- call, do not examine components whose visibility may be -- accidental. while Present (Comp) and then not Is_Prefixed_Call (N) -- When the selector has been resolved to a function then we may be -- looking at a prefixed call which has been preanalyzed already as -- part of a class condition. In such cases it is possible for a -- derived type to declare a component which has the same name as -- a primitive used in a parent's class condition. -- Avoid seeing components as possible interpretations of the -- selected component when this is true. and then not (Inside_Class_Condition_Preanalysis and then Present (Entity (Sel)) and then Ekind (Entity (Sel)) = E_Function) loop if Chars (Comp) = Chars (Sel) and then Is_Visible_Component (Comp, N) then Set_Entity_With_Checks (Sel, Comp); Set_Etype (Sel, Etype (Comp)); if Ekind (Comp) = E_Discriminant then if Is_Unchecked_Union (Base_Type (Prefix_Type)) then Error_Msg_N ("cannot reference discriminant of unchecked union", Sel); end if; if Is_Generic_Type (Prefix_Type) or else Is_Generic_Type (Root_Type (Prefix_Type)) then Set_Original_Discriminant (Sel, Comp); end if; end if; -- Resolve the prefix early otherwise it is not possible to -- build the actual subtype of the component: it may need -- to duplicate this prefix and duplication is only allowed -- on fully resolved expressions. Resolve (Pref); -- Ada 2005 (AI-50217): Check wrong use of incomplete types or -- subtypes in a package specification. -- Example: -- limited with Pkg; -- package Pkg is -- type Acc_Inc is access Pkg.T; -- X : Acc_Inc; -- N : Natural := X.all.Comp; -- ERROR, limited view -- end Pkg; -- Comp is not visible if Nkind (Pref) = N_Explicit_Dereference and then From_Limited_With (Etype (Prefix (Pref))) and then not Is_Potentially_Use_Visible (Etype (Pref)) and then Nkind (Parent (Cunit_Entity (Current_Sem_Unit))) = N_Package_Specification then Error_Msg_NE ("premature usage of incomplete}", Prefix (Pref), Etype (Prefix (Pref))); end if; -- We generally do not need an actual subtype for the case of -- a selection for an indexed component of a non-packed array, -- since, in this case, gigi can find all the necessary bound -- information. However, when the prefix is itself a selected -- component, for example a.b.c (i), gigi may regard a.b.c as -- a dynamic-sized temporary, so we generate an actual subtype -- for this case. Moreover, if the expressions are complex, -- the actual subtype may be needed for constructs generated -- by their analysis. -- We also do not need an actual subtype for the case of a -- first, last, length, or range attribute applied to a -- non-packed array, since gigi can again get the bounds in -- these cases (gigi cannot handle the packed case, since it -- has the bounds of the packed array type, not the original -- bounds of the type). Parent_N := Parent (N); if not Is_Packed (Etype (Comp)) and then (Is_Simple_Indexed_Component (Parent_N) or else (Nkind (Parent_N) = N_Attribute_Reference and then Attribute_Name (Parent_N) in Name_First | Name_Last | Name_Length | Name_Range)) then Set_Etype (N, Etype (Comp)); -- If full analysis is not enabled, we do not generate an -- actual subtype, because in the absence of expansion -- reference to a formal of a protected type, for example, -- will not be properly transformed, and will lead to -- out-of-scope references in gigi. -- In all other cases, we currently build an actual subtype. -- It seems likely that many of these cases can be avoided, -- but right now, the front end makes direct references to the -- bounds (e.g. in generating a length check), and if we do -- not make an actual subtype, we end up getting a direct -- reference to a discriminant, which will not do. elsif Full_Analysis then Act_Decl := Build_Actual_Subtype_Of_Component (Etype (Comp), N); Insert_Action (N, Act_Decl); if No (Act_Decl) then Set_Etype (N, Etype (Comp)); else -- If discriminants were present in the component -- declaration, they have been replaced by the -- actual values in the prefix object. declare Subt : constant Entity_Id := Defining_Identifier (Act_Decl); begin Set_Etype (Subt, Base_Type (Etype (Comp))); Set_Etype (N, Subt); end; end if; -- If Etype (Comp) is an access type whose designated subtype -- is constrained by an unprefixed discriminant value, -- then ideally we would build a new subtype with an -- appropriately prefixed discriminant value and use that -- instead, as is done in Build_Actual_Subtype_Of_Component. -- That turns out to be difficult in this context (with -- Full_Analysis = False, we could be processing a selected -- component that occurs in a Postcondition pragma; -- PPC pragmas are odd because they can contain references -- to formal parameters that occur outside the subprogram). -- So instead we punt on building a new subtype and we -- use the base type instead. This might introduce -- correctness problems if N were the target of an -- assignment (because a required check might be omitted); -- fortunately, that's impossible because a reference to the -- current instance of a type does not denote a variable view -- when the reference occurs within an aspect_specification. -- GNAT's Precondition and Postcondition pragmas follow the -- same rules as a Pre or Post aspect_specification. elsif Has_Discriminant_Dependent_Constraint (Comp) and then Ekind (Etype (Comp)) = E_Access_Subtype and then Constraint_Has_Unprefixed_Discriminant_Reference (Designated_Type (Etype (Comp))) then Set_Etype (N, Base_Type (Etype (Comp))); -- If Full_Analysis not enabled, just set the Etype else Set_Etype (N, Etype (Comp)); end if; -- Force the generation of a mutably tagged type conversion -- when we encounter a special class-wide equivalent type. if Is_Mutably_Tagged_CW_Equivalent_Type (Etype (Pref)) then Make_Mutably_Tagged_Conversion (Pref, Force => True); end if; Check_Implicit_Dereference (N, Etype (N)); return; end if; -- If the prefix is a private extension, check only the visible -- components of the partial view. This must include the tag, -- which can appear in expanded code in a tag check. if Ekind (Type_To_Use) = E_Record_Type_With_Private and then Chars (Sel) /= Name_uTag then exit when Comp = Last_Entity (Type_To_Use); end if; Next_Entity (Comp); end loop; -- Ada 2005 (AI-252): The selected component can be interpreted as -- a prefixed view of a subprogram. Depending on the context, this is -- either a name that can appear in a renaming declaration, or part -- of an enclosing call given in prefix form. -- Ada 2005 (AI05-0030): In the case of dispatching requeue, the -- selected component should resolve to a name. -- Extension feature: Also support calls with prefixed views for -- untagged record types. if Ada_Version >= Ada_2005 and then (Is_Tagged_Type (Prefix_Type) or else Core_Extensions_Allowed) and then not Is_Concurrent_Type (Prefix_Type) then if Nkind (Parent (N)) = N_Generic_Association or else Nkind (Parent (N)) = N_Requeue_Statement or else Nkind (Parent (N)) = N_Subprogram_Renaming_Declaration then if Find_Primitive_Operation (N) then return; end if; elsif Try_By_Protected_Procedure_Prefixed_View then return; -- If the prefix type is the actual for a formal derived type, -- or a derived type thereof, the component inherited from the -- generic parent may not be visible in the actual, but the -- selected component is legal. This case must be handled before -- trying the object.operation notation to avoid reporting -- spurious errors, but must be skipped when Is_Prefixed_Call has -- been set (because that means that this node was resolved to an -- Object.Operation call when the generic unit was analyzed). elsif In_Instance and then not Is_Prefixed_Call (N) and then Is_Tagged_Type (Prefix_Type) and then Try_Selected_Component_In_Instance (Type_To_Use) then return; elsif Try_Object_Operation (N) then return; end if; -- If the transformation fails, it will be necessary to redo the -- analysis with all errors enabled, to indicate candidate -- interpretations and reasons for each failure ??? end if; elsif Is_Private_Type (Prefix_Type) then -- Allow access only to discriminants of the type. If the type has -- no full view, gigi uses the parent type for the components, so we -- do the same here. if No (Full_View (Prefix_Type)) then Type_To_Use := Root_Type (Base_Type (Prefix_Type)); Comp := First_Entity (Type_To_Use); end if; while Present (Comp) loop if Chars (Comp) = Chars (Sel) then if Ekind (Comp) = E_Discriminant then Set_Entity_With_Checks (Sel, Comp); Generate_Reference (Comp, Sel); Set_Etype (Sel, Etype (Comp)); Set_Etype (N, Etype (Comp)); Check_Implicit_Dereference (N, Etype (N)); if Is_Generic_Type (Prefix_Type) or else Is_Generic_Type (Root_Type (Prefix_Type)) then Set_Original_Discriminant (Sel, Comp); end if; -- Before declaring an error, check whether this is tagged -- private type and a call to a primitive operation. elsif Ada_Version >= Ada_2005 and then Is_Tagged_Type (Prefix_Type) and then Try_Object_Operation (N) then return; else Error_Msg_Node_2 := First_Subtype (Prefix_Type); Error_Msg_NE ("invisible selector& for }", N, Sel); Set_Entity (Sel, Any_Id); Set_Etype (N, Any_Type); end if; return; end if; Next_Entity (Comp); end loop; -- Extension feature: Also support calls with prefixed views for -- untagged private types. if Core_Extensions_Allowed then if Try_Object_Operation (N) then return; end if; end if; elsif Is_Concurrent_Type (Prefix_Type) then -- Find visible operation with given name. For a protected type, -- the possible candidates are discriminants, entries or protected -- subprograms. For a task type, the set can only include entries or -- discriminants if the task type is not an enclosing scope. If it -- is an enclosing scope (e.g. in an inner task) then all entities -- are visible, but the prefix must denote the enclosing scope, i.e. -- can only be a direct name or an expanded name. Set_Etype (Sel, Any_Type); Hidden_Comp := Empty; In_Scope := In_Open_Scopes (Prefix_Type); Is_Private_Op := False; while Present (Comp) loop -- Do not examine private operations of the type if not within -- its scope. if Chars (Comp) = Chars (Sel) then if Is_Overloadable (Comp) and then (In_Scope or else Comp /= First_Private_Entity (Type_To_Use)) then Add_One_Interp (Sel, Comp, Etype (Comp)); if Comp = First_Private_Entity (Type_To_Use) then Is_Private_Op := True; end if; -- If the prefix is tagged, the correct interpretation may -- lie in the primitive or class-wide operations of the -- type. Perform a simple conformance check to determine -- whether Try_Object_Operation should be invoked even if -- a visible entity is found. if Is_Tagged_Type (Prefix_Type) and then Nkind (Parent (N)) in N_Function_Call | N_Indexed_Component | N_Procedure_Call_Statement and then Has_Mode_Conformant_Spec (Comp) then Has_Candidate := True; end if; -- Note: a selected component may not denote a component of a -- protected type (4.1.3(7)). elsif Ekind (Comp) in E_Discriminant | E_Entry_Family or else (In_Scope and then not Is_Protected_Type (Prefix_Type) and then Is_Entity_Name (Pref)) then Set_Entity_With_Checks (Sel, Comp); Generate_Reference (Comp, Sel); -- The selector is not overloadable, so we have a candidate -- interpretation. Has_Candidate := True; else if Ekind (Comp) = E_Component then Hidden_Comp := Comp; end if; goto Next_Comp; end if; Set_Etype (Sel, Etype (Comp)); Set_Etype (N, Etype (Comp)); if Ekind (Comp) = E_Discriminant then Set_Original_Discriminant (Sel, Comp); end if; end if; <> if Comp = First_Private_Entity (Type_To_Use) then if Etype (Sel) /= Any_Type then -- If the first private entity's name matches, then treat -- it as a private op: needed for the error check for -- illegal selection of private entities further below. if Chars (Comp) = Chars (Sel) then Is_Private_Op := True; end if; -- We have a candidate, so exit the loop exit; else -- Indicate that subsequent operations are private, -- for better error reporting. Is_Private_Op := True; end if; end if; -- Do not examine private operations if not within scope of -- the synchronized type. exit when not In_Scope and then Comp = First_Private_Entity (Base_Type (Prefix_Type)); Next_Entity (Comp); end loop; -- If the scope is a current instance, the prefix cannot be an -- expression of the same type, unless the selector designates a -- public operation (otherwise that would represent an attempt to -- reach an internal entity of another synchronized object). -- This is legal if prefix is an access to such type and there is -- a dereference, or is a component with a dereferenced prefix. -- It is also legal if the prefix is a component of a task type, -- and the selector is one of the task operations. if In_Scope and then not Is_Entity_Name (Pref) and then not Has_Dereference (Pref) then if Is_Task_Type (Prefix_Type) and then Present (Entity (Sel)) and then Is_Entry (Entity (Sel)) then null; elsif Is_Protected_Type (Prefix_Type) and then Is_Overloadable (Entity (Sel)) and then not Is_Private_Op then null; else Error_Msg_NE ("invalid reference to internal operation of some object of " & "type &", N, Type_To_Use); Set_Entity (Sel, Any_Id); Set_Etype (Sel, Any_Type); return; end if; -- Another special case: the prefix may denote an object of the type -- (but not a type) in which case this is an external call and the -- operation must be public. elsif In_Scope and then Is_Object_Reference (Original_Node (Prefix (N))) and then Comes_From_Source (N) and then Is_Private_Op then if Present (Hidden_Comp) then Error_Msg_NE ("invalid reference to private component of object of type " & "&", N, Type_To_Use); else Error_Msg_NE ("invalid reference to private operation of some object of " & "type &", N, Type_To_Use); end if; Set_Entity (Sel, Any_Id); Set_Etype (Sel, Any_Type); return; end if; -- If there is no visible entity with the given name or none of the -- visible entities are plausible interpretations, check whether -- there is some other primitive operation with that name. if Ada_Version >= Ada_2005 and then Is_Tagged_Type (Prefix_Type) then if (Etype (N) = Any_Type or else not Has_Candidate) and then Try_Object_Operation (N) then return; -- If the context is not syntactically a procedure call, it -- may be a call to a primitive function declared outside of -- the synchronized type. -- If the context is a procedure call, there might still be -- an overloading between an entry and a primitive procedure -- declared outside of the synchronized type, called in prefix -- notation. This is harder to disambiguate because in one case -- the controlling formal is implicit ??? elsif Nkind (Parent (N)) /= N_Procedure_Call_Statement and then Nkind (Parent (N)) /= N_Indexed_Component and then Try_Object_Operation (N) then return; end if; -- Ada 2012 (AI05-0090-1): If we found a candidate of a call to an -- entry or procedure of a tagged concurrent type we must check -- if there are class-wide subprograms covering the primitive. If -- true then Try_Object_Operation reports the error. if Has_Candidate and then Is_Concurrent_Type (Prefix_Type) and then Nkind (Parent (N)) = N_Procedure_Call_Statement then -- Duplicate the call. This is required to avoid problems with -- the tree transformations performed by Try_Object_Operation. -- Set properly the parent of the copied call, because it is -- about to be reanalyzed. declare Par : constant Node_Id := New_Copy_Tree (Parent (N)); begin Set_Parent (Par, Parent (Parent (N))); if Try_Object_Operation (Sinfo.Nodes.Name (Par), CW_Test_Only => True) then return; end if; end; end if; end if; if Etype (N) = Any_Type and then Is_Protected_Type (Prefix_Type) then -- Case of a prefix of a protected type: selector might denote -- an invisible private component. Comp := First_Private_Entity (Base_Type (Prefix_Type)); while Present (Comp) and then Chars (Comp) /= Chars (Sel) loop Next_Entity (Comp); end loop; if Present (Comp) then if Is_Single_Concurrent_Object then Error_Msg_Node_2 := Entity (Pref); Error_Msg_NE ("invisible selector& for &", N, Sel); else Error_Msg_Node_2 := First_Subtype (Prefix_Type); Error_Msg_NE ("invisible selector& for }", N, Sel); end if; return; end if; end if; Set_Is_Overloaded (N, Is_Overloaded (Sel)); -- Extension feature: Also support calls with prefixed views for -- untagged types. elsif Core_Extensions_Allowed and then Try_Object_Operation (N) then return; else -- Invalid prefix Error_Msg_NE ("invalid prefix in selected component&", N, Sel); end if; -- If N still has no type, the component is not defined in the prefix if Etype (N) = Any_Type then if Is_Single_Concurrent_Object then Error_Msg_Node_2 := Entity (Pref); Error_Msg_NE ("no selector& for&", N, Sel); Check_Misspelled_Selector (Type_To_Use, Sel); -- If this is a derived formal type, the parent may have different -- visibility at this point. Try for an inherited component before -- reporting an error. elsif Is_Generic_Type (Prefix_Type) and then Ekind (Prefix_Type) = E_Record_Type_With_Private and then Prefix_Type /= Etype (Prefix_Type) and then Is_Record_Type (Etype (Prefix_Type)) then Set_Etype (Prefix (N), Etype (Prefix_Type)); Analyze_Selected_Component (N); return; -- Similarly, if this is the actual for a formal derived type, or -- a derived type thereof, the component inherited from the generic -- parent may not be visible in the actual, but the selected -- component is legal. elsif In_Instance and then Is_Tagged_Type (Prefix_Type) then -- Climb up the derivation chain of the generic parent type until -- we find the proper ancestor type. if Try_Selected_Component_In_Instance (Type_To_Use) then return; -- The search above must have eventually succeeded, since the -- selected component was legal in the generic. else raise Program_Error; end if; -- Component not found, specialize error message when appropriate else if Ekind (Prefix_Type) = E_Record_Subtype then -- Check whether this is a component of the base type which -- is absent from a statically constrained subtype. This will -- raise constraint error at run time, but is not a compile- -- time error. When the selector is illegal for base type as -- well fall through and generate a compilation error anyway. Comp := First_Component (Base_Type (Prefix_Type)); while Present (Comp) loop if Chars (Comp) = Chars (Sel) and then Is_Visible_Component (Comp, Sel) then Set_Entity_With_Checks (Sel, Comp); Generate_Reference (Comp, Sel); Set_Etype (Sel, Etype (Comp)); Set_Etype (N, Etype (Comp)); -- Emit appropriate message. The node will be replaced -- by an appropriate raise statement. -- Note that in GNATprove mode, as with all calls to -- apply a compile time constraint error, this will be -- made into an error to simplify the processing of the -- formal verification backend. Apply_Compile_Time_Constraint_Error (N, "component not present in }??", CE_Discriminant_Check_Failed, Ent => Prefix_Type, Emit_Message => GNATprove_Mode or not In_Instance_Not_Visible); return; end if; Next_Component (Comp); end loop; end if; Error_Msg_Node_2 := First_Subtype (Prefix_Type); Error_Msg_NE ("no selector& for}", N, Sel); -- Add information in the case of an incomplete prefix if Is_Incomplete_Type (Type_To_Use) then declare Inc : constant Entity_Id := First_Subtype (Type_To_Use); begin if From_Limited_With (Scope (Type_To_Use)) then Error_Msg_NE ("\limited view of& has no components", N, Inc); else Error_Msg_NE ("\premature usage of incomplete type&", N, Inc); if Nkind (Parent (Inc)) = N_Incomplete_Type_Declaration then -- Record location of premature use in entity so that -- a continuation message is generated when the -- completion is seen. Set_Premature_Use (Parent (Inc), N); end if; end if; end; end if; Check_Misspelled_Selector (Type_To_Use, Sel); end if; Set_Entity (Sel, Any_Id); Set_Etype (Sel, Any_Type); end if; end Analyze_Selected_Component; --------------------------- -- Analyze_Short_Circuit -- --------------------------- procedure Analyze_Short_Circuit (N : Node_Id) is L : constant Node_Id := Left_Opnd (N); R : constant Node_Id := Right_Opnd (N); Ind : Interp_Index; It : Interp; begin Set_Etype (N, Any_Type); Analyze_Expression (L); Analyze_Expression (R); if not Is_Overloaded (L) then if Root_Type (Etype (L)) = Standard_Boolean and then Has_Compatible_Type (R, Etype (L)) then Add_One_Interp (N, Etype (L), Etype (L)); end if; else Get_First_Interp (L, Ind, It); while Present (It.Typ) loop if Root_Type (It.Typ) = Standard_Boolean and then Has_Compatible_Type (R, It.Typ) then Add_One_Interp (N, It.Typ, It.Typ); end if; Get_Next_Interp (Ind, It); end loop; end if; -- Here we have failed to find an interpretation. Clearly we know that -- it is not the case that both operands can have an interpretation of -- Boolean, but this is by far the most likely intended interpretation. -- So we simply resolve both operands as Booleans, and at least one of -- these resolutions will generate an error message, and we do not need -- to give another error message on the short circuit operation itself. if Etype (N) = Any_Type then Resolve (L, Standard_Boolean); Resolve (R, Standard_Boolean); Set_Etype (N, Standard_Boolean); end if; if Style_Check then if Nkind (L) not in N_Short_Circuit | N_Op_And | N_Op_Or | N_Op_Xor then Check_Xtra_Parens_Precedence (L); end if; if Nkind (R) not in N_Short_Circuit | N_Op_And | N_Op_Or | N_Op_Xor then Check_Xtra_Parens_Precedence (R); end if; end if; end Analyze_Short_Circuit; ------------------- -- Analyze_Slice -- ------------------- procedure Analyze_Slice (N : Node_Id) is D : constant Node_Id := Discrete_Range (N); P : constant Node_Id := Prefix (N); Array_Type : Entity_Id; Index_Type : Entity_Id; procedure Analyze_Overloaded_Slice; -- If the prefix is overloaded, select those interpretations that -- yield a one-dimensional array type. ------------------------------ -- Analyze_Overloaded_Slice -- ------------------------------ procedure Analyze_Overloaded_Slice is I : Interp_Index; It : Interp; Typ : Entity_Id; begin Set_Etype (N, Any_Type); Get_First_Interp (P, I, It); while Present (It.Nam) loop Typ := It.Typ; if Is_Access_Type (Typ) then Typ := Designated_Type (Typ); Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); end if; if Is_Array_Type (Typ) and then Number_Dimensions (Typ) = 1 and then Has_Compatible_Type (D, Etype (First_Index (Typ))) then Add_One_Interp (N, Typ, Typ); end if; Get_Next_Interp (I, It); end loop; if Etype (N) = Any_Type then Error_Msg_N ("expect array type in prefix of slice", N); end if; end Analyze_Overloaded_Slice; -- Start of processing for Analyze_Slice begin Analyze (P); Analyze (D); if Is_Overloaded (P) then Analyze_Overloaded_Slice; else Array_Type := Etype (P); Set_Etype (N, Any_Type); if Is_Access_Type (Array_Type) then Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); Array_Type := Implicitly_Designated_Type (Array_Type); end if; if not Is_Array_Type (Array_Type) then Wrong_Type (P, Any_Array); elsif Number_Dimensions (Array_Type) > 1 then Error_Msg_N ("type is not one-dimensional array in slice prefix", N); else if Ekind (Array_Type) = E_String_Literal_Subtype then Index_Type := Etype (String_Literal_Low_Bound (Array_Type)); else Index_Type := Etype (First_Index (Array_Type)); end if; if not Has_Compatible_Type (D, Index_Type) then Wrong_Type (D, Index_Type); else Set_Etype (N, Array_Type); end if; end if; end if; end Analyze_Slice; ----------------------------- -- Analyze_Type_Conversion -- ----------------------------- procedure Analyze_Type_Conversion (N : Node_Id) is Expr : constant Node_Id := Expression (N); Mark : constant Entity_Id := Subtype_Mark (N); Typ : Entity_Id; begin -- If Conversion_OK is set, then the Etype is already set, and the only -- processing required is to analyze the expression. This is used to -- construct certain "illegal" conversions which are not allowed by Ada -- semantics, but can be handled by Gigi, see Sinfo for further details. if Conversion_OK (N) then Analyze (Expr); return; end if; -- Otherwise full type analysis is required, as well as some semantic -- checks to make sure the argument of the conversion is appropriate. Find_Type (Mark); Typ := Entity (Mark); Set_Etype (N, Typ); Analyze_Expression (Expr); Check_Fully_Declared (Typ, N); Validate_Remote_Type_Type_Conversion (N); -- Only remaining step is validity checks on the argument. These -- are skipped if the conversion does not come from the source. if not Comes_From_Source (N) then return; -- If there was an error in a generic unit, no need to replicate the -- error message. Conversely, constant-folding in the generic may -- transform the argument of a conversion into a string literal, which -- is legal. Therefore the following tests are not performed in an -- instance. The same applies to an inlined body. elsif In_Instance or In_Inlined_Body then return; elsif Nkind (Expr) = N_Null then Error_Msg_N ("argument of conversion cannot be null", N); Error_Msg_N ("\use qualified expression instead", N); Set_Etype (N, Any_Type); elsif Nkind (Expr) = N_Aggregate then Error_Msg_N ("argument of conversion cannot be aggregate", N); Error_Msg_N ("\use qualified expression instead", N); elsif Nkind (Expr) = N_Allocator then Error_Msg_N ("argument of conversion cannot be allocator", N); Error_Msg_N ("\use qualified expression instead", N); elsif Nkind (Expr) = N_String_Literal then Error_Msg_N ("argument of conversion cannot be string literal", N); Error_Msg_N ("\use qualified expression instead", N); elsif Nkind (Expr) = N_Character_Literal then if Ada_Version = Ada_83 then Resolve (Expr, Typ); else Error_Msg_N ("argument of conversion cannot be character literal", N); Error_Msg_N ("\use qualified expression instead", N); end if; elsif Nkind (Expr) = N_Attribute_Reference and then Attribute_Name (Expr) in Name_Access | Name_Unchecked_Access | Name_Unrestricted_Access then Error_Msg_N ("argument of conversion cannot be access attribute", N); Error_Msg_N ("\use qualified expression instead", N); end if; -- A formal parameter of a specific tagged type whose related subprogram -- is subject to pragma Extensions_Visible with value "False" cannot -- appear in a class-wide conversion (SPARK RM 6.1.7(3)). Do not check -- internally generated expressions. if Is_Class_Wide_Type (Typ) and then Comes_From_Source (Expr) and then Is_EVF_Expression (Expr) then Error_Msg_N ("formal parameter cannot be converted to class-wide type when " & "Extensions_Visible is False", Expr); end if; -- Perform special checking for access to mutably tagged type since they -- are not compatible with interfaces. if Is_Access_Type (Typ) and then Is_Access_Type (Etype (Expr)) and then not Error_Posted (N) then if Is_Mutably_Tagged_Type (Directly_Designated_Type (Typ)) and then Is_Interface (Directly_Designated_Type (Etype (Expr))) then Error_Msg_N ("argument of conversion to mutably tagged access type cannot " & "be access to interface", Expr); elsif Is_Mutably_Tagged_Type (Directly_Designated_Type (Etype (Expr))) and then Is_Interface (Directly_Designated_Type (Typ)) then Error_Msg_N ("argument of conversion to interface access type cannot " & "be access to mutably tagged type", Expr); end if; end if; end Analyze_Type_Conversion; ---------------------- -- Analyze_Unary_Op -- ---------------------- procedure Analyze_Unary_Op (N : Node_Id) is R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id; begin Set_Etype (N, Any_Type); Candidate_Type := Empty; Analyze_Expression (R); -- If the entity is already set, the node is the instantiation of a -- generic node with a non-local reference, or was manufactured by a -- call to Make_Op_xxx. In either case the entity is known to be valid, -- and we do not need to collect interpretations, instead we just get -- the single possible interpretation. if Present (Entity (N)) then Op_Id := Entity (N); if Ekind (Op_Id) = E_Operator then Find_Unary_Types (R, Op_Id, N); else Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; else Op_Id := Get_Name_Entity_Id (Chars (N)); while Present (Op_Id) loop if Ekind (Op_Id) = E_Operator then if No (Next_Entity (First_Entity (Op_Id))) then Find_Unary_Types (R, Op_Id, N); end if; elsif Is_Overloadable (Op_Id) then Analyze_User_Defined_Unary_Op (N, Op_Id); end if; Op_Id := Homonym (Op_Id); end loop; end if; Operator_Check (N); end Analyze_Unary_Op; ---------------------------------- -- Analyze_Unchecked_Expression -- ---------------------------------- procedure Analyze_Unchecked_Expression (N : Node_Id) is Expr : constant Node_Id := Expression (N); begin Analyze (Expr, Suppress => All_Checks); Set_Etype (N, Etype (Expr)); Save_Interps (Expr, N); end Analyze_Unchecked_Expression; --------------------------------------- -- Analyze_Unchecked_Type_Conversion -- --------------------------------------- procedure Analyze_Unchecked_Type_Conversion (N : Node_Id) is Expr : constant Node_Id := Expression (N); Mark : constant Entity_Id := Subtype_Mark (N); begin Find_Type (Mark); Set_Etype (N, Entity (Mark)); Analyze_Expression (Expr); end Analyze_Unchecked_Type_Conversion; ------------------------------------ -- Analyze_User_Defined_Binary_Op -- ------------------------------------ procedure Analyze_User_Defined_Binary_Op (N : Node_Id; Op_Id : Entity_Id) is begin declare F1 : constant Entity_Id := First_Formal (Op_Id); F2 : constant Entity_Id := Next_Formal (F1); begin -- Verify that Op_Id is a visible binary function. Note that since -- we know Op_Id is overloaded, potentially use visible means use -- visible for sure (RM 9.4(11)). Be prepared for previous errors. if Ekind (Op_Id) = E_Function and then Present (F2) and then (Is_Immediately_Visible (Op_Id) or else Is_Potentially_Use_Visible (Op_Id)) and then (Has_Compatible_Type (Left_Opnd (N), Etype (F1)) or else Etype (F1) = Any_Type) and then (Has_Compatible_Type (Right_Opnd (N), Etype (F2)) or else Etype (F2) = Any_Type) then Add_One_Interp (N, Op_Id, Base_Type (Etype (Op_Id))); -- If the operands are overloaded, indicate that the current -- type is a viable candidate. This is redundant in most cases, -- but for equality and comparison operators where the context -- does not impose a type on the operands, setting the proper -- type is necessary to avoid subsequent ambiguities during -- resolution, when both user-defined and predefined operators -- may be candidates. if Is_Overloaded (Left_Opnd (N)) then Set_Etype (Left_Opnd (N), Etype (F1)); end if; if Is_Overloaded (Right_Opnd (N)) then Set_Etype (Right_Opnd (N), Etype (F2)); end if; if Debug_Flag_E then Write_Str ("user defined operator "); Write_Name (Chars (Op_Id)); Write_Str (" on node "); Write_Int (Int (N)); Write_Eol; end if; end if; end; end Analyze_User_Defined_Binary_Op; ----------------------------------- -- Analyze_User_Defined_Unary_Op -- ----------------------------------- procedure Analyze_User_Defined_Unary_Op (N : Node_Id; Op_Id : Entity_Id) is begin -- Only do analysis if the operator Comes_From_Source, since otherwise -- the operator was generated by the expander, and all such operators -- always refer to the operators in package Standard. if Comes_From_Source (N) then declare F : constant Entity_Id := First_Formal (Op_Id); begin -- Verify that Op_Id is a visible unary function. Note that since -- we know Op_Id is overloaded, potentially use visible means use -- visible for sure (RM 9.4(11)). if Ekind (Op_Id) = E_Function and then No (Next_Formal (F)) and then (Is_Immediately_Visible (Op_Id) or else Is_Potentially_Use_Visible (Op_Id)) and then Has_Compatible_Type (Right_Opnd (N), Etype (F)) then Add_One_Interp (N, Op_Id, Etype (Op_Id)); end if; end; end if; end Analyze_User_Defined_Unary_Op; --------------------------- -- Check_Arithmetic_Pair -- --------------------------- procedure Check_Arithmetic_Pair (T1, T2 : Entity_Id; Op_Id : Entity_Id; N : Node_Id) is Op_Name : constant Name_Id := Chars (Op_Id); function Has_Fixed_Op (Typ : Entity_Id; Op : Entity_Id) return Boolean; -- Check whether the fixed-point type Typ has a user-defined operator -- (multiplication or division) that should hide the corresponding -- predefined operator. Used to implement Ada 2005 AI-264, to make -- such operators more visible and therefore useful. -- -- If the name of the operation is an expanded name with prefix -- Standard, the predefined universal fixed operator is available, -- as specified by AI-420 (RM 4.5.5 (19.1/2)). ------------------ -- Has_Fixed_Op -- ------------------ function Has_Fixed_Op (Typ : Entity_Id; Op : Entity_Id) return Boolean is Bas : constant Entity_Id := Base_Type (Typ); Ent : Entity_Id; F1 : Entity_Id; F2 : Entity_Id; begin -- If the universal_fixed operation is given explicitly the rule -- concerning primitive operations of the type do not apply. if Nkind (N) = N_Function_Call and then Nkind (Name (N)) = N_Expanded_Name and then Entity (Prefix (Name (N))) = Standard_Standard then return False; end if; -- The operation is treated as primitive if it is declared in the -- same scope as the type, and therefore on the same entity chain. Ent := Next_Entity (Typ); while Present (Ent) loop if Chars (Ent) = Chars (Op) then F1 := First_Formal (Ent); F2 := Next_Formal (F1); -- The operation counts as primitive if either operand or -- result are of the given base type, and both operands are -- fixed point types. if (Base_Type (Etype (F1)) = Bas and then Is_Fixed_Point_Type (Etype (F2))) or else (Base_Type (Etype (F2)) = Bas and then Is_Fixed_Point_Type (Etype (F1))) or else (Base_Type (Etype (Ent)) = Bas and then Is_Fixed_Point_Type (Etype (F1)) and then Is_Fixed_Point_Type (Etype (F2))) then return True; end if; end if; Next_Entity (Ent); end loop; return False; end Has_Fixed_Op; -- Start of processing for Check_Arithmetic_Pair begin if Op_Name in Name_Op_Add | Name_Op_Subtract then if Is_Numeric_Type (T1) and then Is_Numeric_Type (T2) and then (Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1)) and then Is_Effectively_Visible_Operator (N, Specific_Type (T1, T2)) then Add_One_Interp (N, Op_Id, Specific_Type (T1, T2)); end if; elsif Op_Name in Name_Op_Multiply | Name_Op_Divide then if Is_Fixed_Point_Type (T1) and then (Is_Fixed_Point_Type (T2) or else T2 = Universal_Real) then -- Add one interpretation with universal fixed result if not Has_Fixed_Op (T1, Op_Id) or else Nkind (Parent (N)) = N_Type_Conversion then Add_One_Interp (N, Op_Id, Universal_Fixed); end if; elsif Is_Fixed_Point_Type (T2) and then T1 = Universal_Real and then (not Has_Fixed_Op (T1, Op_Id) or else Nkind (Parent (N)) = N_Type_Conversion) then Add_One_Interp (N, Op_Id, Universal_Fixed); elsif Is_Numeric_Type (T1) and then Is_Numeric_Type (T2) and then (Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1)) and then Is_Effectively_Visible_Operator (N, Specific_Type (T1, T2)) then Add_One_Interp (N, Op_Id, Specific_Type (T1, T2)); elsif Is_Fixed_Point_Type (T1) and then (Base_Type (T2) = Base_Type (Standard_Integer) or else T2 = Universal_Integer) then Add_One_Interp (N, Op_Id, T1); elsif T2 = Universal_Real and then Base_Type (T1) = Base_Type (Standard_Integer) and then Op_Name = Name_Op_Multiply then Add_One_Interp (N, Op_Id, Any_Fixed); elsif T1 = Universal_Real and then Base_Type (T2) = Base_Type (Standard_Integer) then Add_One_Interp (N, Op_Id, Any_Fixed); elsif Is_Fixed_Point_Type (T2) and then (Base_Type (T1) = Base_Type (Standard_Integer) or else T1 = Universal_Integer) and then Op_Name = Name_Op_Multiply then Add_One_Interp (N, Op_Id, T2); elsif T1 = Universal_Real and then T2 = Universal_Integer then Add_One_Interp (N, Op_Id, T1); elsif T2 = Universal_Real and then T1 = Universal_Integer and then Op_Name = Name_Op_Multiply then Add_One_Interp (N, Op_Id, T2); end if; elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then if Is_Integer_Type (T1) and then (Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1)) and then Is_Effectively_Visible_Operator (N, Specific_Type (T1, T2)) then Add_One_Interp (N, Op_Id, Specific_Type (T1, T2)); end if; elsif Op_Name = Name_Op_Expon then if Is_Numeric_Type (T1) and then not Is_Fixed_Point_Type (T1) and then (Base_Type (T2) = Base_Type (Standard_Integer) or else T2 = Universal_Integer) then Add_One_Interp (N, Op_Id, Base_Type (T1)); end if; else pragma Assert (Nkind (N) in N_Op_Shift); -- If not one of the predefined operators, the node may be one -- of the intrinsic functions. Its kind is always specific, and -- we can use it directly, rather than the name of the operation. if Is_Integer_Type (T1) and then (Base_Type (T2) = Base_Type (Standard_Integer) or else T2 = Universal_Integer) then Add_One_Interp (N, Op_Id, Base_Type (T1)); end if; end if; end Check_Arithmetic_Pair; ------------------------------- -- Check_Misspelled_Selector -- ------------------------------- procedure Check_Misspelled_Selector (Prefix : Entity_Id; Sel : Node_Id) is Max_Suggestions : constant := 2; Nr_Of_Suggestions : Natural := 0; Suggestion_1 : Entity_Id := Empty; Suggestion_2 : Entity_Id := Empty; Comp : Entity_Id; begin -- All the components of the prefix of selector Sel are matched against -- Sel and a count is maintained of possible misspellings. When at -- the end of the analysis there are one or two (not more) possible -- misspellings, these misspellings will be suggested as possible -- correction. if not (Is_Private_Type (Prefix) or else Is_Record_Type (Prefix)) then -- Concurrent types should be handled as well ??? return; end if; Comp := First_Entity (Prefix); while Nr_Of_Suggestions <= Max_Suggestions and then Present (Comp) loop if Is_Visible_Component (Comp, Sel) then if Is_Bad_Spelling_Of (Chars (Comp), Chars (Sel)) then Nr_Of_Suggestions := Nr_Of_Suggestions + 1; case Nr_Of_Suggestions is when 1 => Suggestion_1 := Comp; when 2 => Suggestion_2 := Comp; when others => null; end case; end if; end if; Next_Entity (Comp); end loop; -- Report at most two suggestions if Nr_Of_Suggestions = 1 then Error_Msg_NE -- CODEFIX ("\possible misspelling of&", Sel, Suggestion_1); elsif Nr_Of_Suggestions = 2 then Error_Msg_Node_2 := Suggestion_2; Error_Msg_NE -- CODEFIX ("\possible misspelling of& or&", Sel, Suggestion_1); end if; end Check_Misspelled_Selector; ------------------- -- Diagnose_Call -- ------------------- procedure Diagnose_Call (N : Node_Id; Nam : Node_Id) is Actual : Node_Id; X : Interp_Index; It : Interp; Err_Mode : Boolean; New_Nam : Node_Id; Num_Actuals : Natural; Num_Interps : Natural; Void_Interp_Seen : Boolean := False; Success : Boolean; pragma Warnings (Off, Boolean); begin Num_Actuals := 0; Actual := First_Actual (N); while Present (Actual) loop -- Ada 2005 (AI-50217): Post an error in case of premature -- usage of an entity from the limited view. if not Analyzed (Etype (Actual)) and then From_Limited_With (Etype (Actual)) and then Ada_Version >= Ada_2005 then Error_Msg_Qual_Level := 1; Error_Msg_NE ("missing with_clause for scope of imported type&", Actual, Etype (Actual)); Error_Msg_Qual_Level := 0; end if; Num_Actuals := Num_Actuals + 1; Next_Actual (Actual); end loop; -- Before listing the possible candidates, check whether this is -- a prefix of a selected component that has been rewritten as a -- parameterless function call because there is a callable candidate -- interpretation. If there is a hidden package in the list of homonyms -- of the function name (bad programming style in any case) suggest that -- this is the intended entity. if No (Parameter_Associations (N)) and then Nkind (Parent (N)) = N_Selected_Component and then Nkind (Parent (Parent (N))) in N_Declaration and then Is_Overloaded (Nam) then declare Ent : Entity_Id; begin Ent := Current_Entity (Nam); while Present (Ent) loop if Ekind (Ent) = E_Package then Error_Msg_N ("no legal interpretations as function call,!", Nam); Error_Msg_NE ("\package& is not visible", N, Ent); Rewrite (Parent (N), New_Occurrence_Of (Any_Type, Sloc (N))); return; end if; Ent := Homonym (Ent); end loop; end; end if; -- If this is a call to an operation of a concurrent type, the failed -- interpretations have been removed from the name. Recover them now -- in order to provide full diagnostics. if Nkind (Parent (Nam)) = N_Selected_Component then Set_Entity (Nam, Empty); New_Nam := New_Copy_Tree (Parent (Nam)); Set_Is_Overloaded (New_Nam, False); Set_Is_Overloaded (Selector_Name (New_Nam), False); Set_Parent (New_Nam, Parent (Parent (Nam))); Analyze_Selected_Component (New_Nam); Get_First_Interp (Selector_Name (New_Nam), X, It); else Get_First_Interp (Nam, X, It); end if; -- If the number of actuals is 2, then remove interpretations involving -- a unary "+" operator as they might yield confusing errors downstream. if Num_Actuals = 2 and then Nkind (Parent (Nam)) /= N_Selected_Component then Num_Interps := 0; while Present (It.Nam) loop if Ekind (It.Nam) = E_Operator and then Chars (It.Nam) = Name_Op_Add and then (No (First_Formal (It.Nam)) or else No (Next_Formal (First_Formal (It.Nam)))) then Remove_Interp (X); else Num_Interps := Num_Interps + 1; end if; Get_Next_Interp (X, It); end loop; if Num_Interps = 0 then Error_Msg_N ("!too many arguments in call to&", Nam); return; end if; Get_First_Interp (Nam, X, It); else Num_Interps := 2; -- at least end if; -- Analyze each candidate call again with full error reporting for each if Num_Interps > 1 then Error_Msg_N ("!no candidate interpretations match the actuals:", Nam); end if; Err_Mode := All_Errors_Mode; All_Errors_Mode := True; while Present (It.Nam) loop if Etype (It.Nam) = Standard_Void_Type then Void_Interp_Seen := True; end if; Analyze_One_Call (N, It.Nam, True, Success); Get_Next_Interp (X, It); end loop; if Nkind (N) = N_Function_Call then Get_First_Interp (Nam, X, It); if No (It.Typ) and then Ekind (Entity (Name (N))) = E_Function and then Present (Homonym (Entity (Name (N)))) then -- A name may appear overloaded if it has a homonym, even if that -- homonym is non-overloadable, in which case the overload list is -- in fact empty. This specialized case deserves a special message -- if the homonym is a child package. declare Nam : constant Node_Id := Name (N); H : constant Entity_Id := Homonym (Entity (Nam)); begin if Ekind (H) = E_Package and then Is_Child_Unit (H) then Error_Msg_Qual_Level := 2; Error_Msg_NE ("if an entity in package& is meant, ", Nam, H); Error_Msg_NE ("\use a fully qualified name", Nam, H); Error_Msg_Qual_Level := 0; end if; end; else while Present (It.Nam) loop if Ekind (It.Nam) in E_Function | E_Operator then return; else Get_Next_Interp (X, It); end if; end loop; -- If all interpretations are procedures, this deserves a more -- precise message. Ditto if this appears as the prefix of a -- selected component, which may be a lexical error. Error_Msg_N ("\context requires function call, found procedure name", Nam); if Nkind (Parent (N)) = N_Selected_Component and then N = Prefix (Parent (N)) then Error_Msg_N -- CODEFIX ("\period should probably be semicolon", Parent (N)); end if; end if; elsif Nkind (N) = N_Procedure_Call_Statement and then not Void_Interp_Seen then Error_Msg_N ("\function name found in procedure call", Nam); end if; All_Errors_Mode := Err_Mode; end Diagnose_Call; --------------------------- -- Find_Arithmetic_Types -- --------------------------- procedure Find_Arithmetic_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id) is procedure Check_Right_Argument (T : Entity_Id); -- Check right operand of operator -------------------------- -- Check_Right_Argument -- -------------------------- procedure Check_Right_Argument (T : Entity_Id) is I : Interp_Index; It : Interp; begin if not Is_Overloaded (R) then Check_Arithmetic_Pair (T, Etype (R), Op_Id, N); else Get_First_Interp (R, I, It); while Present (It.Typ) loop Check_Arithmetic_Pair (T, It.Typ, Op_Id, N); Get_Next_Interp (I, It); end loop; end if; end Check_Right_Argument; -- Local variables I : Interp_Index; It : Interp; -- Start of processing for Find_Arithmetic_Types begin if not Is_Overloaded (L) then Check_Right_Argument (Etype (L)); else Get_First_Interp (L, I, It); while Present (It.Typ) loop Check_Right_Argument (It.Typ); Get_Next_Interp (I, It); end loop; end if; end Find_Arithmetic_Types; ------------------------ -- Find_Boolean_Types -- ------------------------ procedure Find_Boolean_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id) is procedure Check_Boolean_Pair (T1, T2 : Entity_Id); -- Check operand pair of operator procedure Check_Right_Argument (T : Entity_Id); -- Check right operand of operator ------------------------ -- Check_Boolean_Pair -- ------------------------ procedure Check_Boolean_Pair (T1, T2 : Entity_Id) is T : Entity_Id; begin if Valid_Boolean_Arg (T1) and then Valid_Boolean_Arg (T2) and then (Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1)) then T := Specific_Type (T1, T2); if T = Universal_Integer then T := Any_Modular; end if; -- test Is_Effectively_Visible_Operator here ??? Add_One_Interp (N, Op_Id, T); end if; end Check_Boolean_Pair; -------------------------- -- Check_Right_Argument -- -------------------------- procedure Check_Right_Argument (T : Entity_Id) is I : Interp_Index; It : Interp; begin -- Defend against previous error if Nkind (R) = N_Error then null; elsif not Is_Overloaded (R) then Check_Boolean_Pair (T, Etype (R)); else Get_First_Interp (R, I, It); while Present (It.Typ) loop Check_Boolean_Pair (T, It.Typ); Get_Next_Interp (I, It); end loop; end if; end Check_Right_Argument; -- Local variables I : Interp_Index; It : Interp; -- Start of processing for Find_Boolean_Types begin if not Is_Overloaded (L) then Check_Right_Argument (Etype (L)); else Get_First_Interp (L, I, It); while Present (It.Typ) loop Check_Right_Argument (It.Typ); Get_Next_Interp (I, It); end loop; end if; end Find_Boolean_Types; ------------------------------------ -- Find_Comparison_Equality_Types -- ------------------------------------ -- The context of the operator plays no role in resolving the operands, -- so that if there is more than one interpretation of the operands that -- is compatible with the comparison or equality, then the operation is -- ambiguous, but this cannot be reported at this point because there is -- no guarantee that the operation will be resolved to this operator yet. procedure Find_Comparison_Equality_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id) is Op_Name : constant Name_Id := Chars (Op_Id); Op_Typ : Entity_Id renames Standard_Boolean; function Try_Left_Interp (T : Entity_Id) return Entity_Id; -- Try an interpretation of the left operand with type T. Return the -- type of the interpretation of the right operand making up a valid -- operand pair, or else Any_Type if the right operand is ambiguous, -- otherwise Empty if no such pair exists. function Is_Valid_Comparison_Type (T : Entity_Id) return Boolean; -- Return true if T is a valid comparison type function Is_Valid_Equality_Type (T : Entity_Id; Anon_Access : Boolean) return Boolean; -- Return true if T is a valid equality type function Is_Valid_Pair (T1, T2 : Entity_Id) return Boolean; -- Return true if T1 and T2 constitute a valid pair of operand types for -- L and R respectively. --------------------- -- Try_Left_Interp -- --------------------- function Try_Left_Interp (T : Entity_Id) return Entity_Id is I : Interp_Index; It : Interp; R_Typ : Entity_Id; Valid_I : Interp_Index; begin -- Defend against previous error if Nkind (R) = N_Error then null; -- Loop through the interpretations of the right operand elsif not Is_Overloaded (R) then if Is_Valid_Pair (T, Etype (R)) then return Etype (R); end if; else R_Typ := Empty; Valid_I := 0; Get_First_Interp (R, I, It); while Present (It.Typ) loop if Is_Valid_Pair (T, It.Typ) then -- If several interpretations are possible, disambiguate if Present (R_Typ) and then Base_Type (It.Typ) /= Base_Type (R_Typ) then It := Disambiguate (R, Valid_I, I, Any_Type); if It = No_Interp then R_Typ := Any_Type; exit; end if; else Valid_I := I; end if; R_Typ := It.Typ; end if; Get_Next_Interp (I, It); end loop; if Present (R_Typ) then return R_Typ; end if; end if; return Empty; end Try_Left_Interp; ------------------------------ -- Is_Valid_Comparison_Type -- ------------------------------ function Is_Valid_Comparison_Type (T : Entity_Id) return Boolean is begin -- The operation must be performed in a context where the operators -- of the base type are visible. if Is_Visible_Operator (N, Base_Type (T)) then null; -- Save candidate type for subsequent error message, if any else if Valid_Comparison_Arg (T) then Candidate_Type := T; end if; return False; end if; -- Defer to the common implementation for the rest return Valid_Comparison_Arg (T); end Is_Valid_Comparison_Type; ---------------------------- -- Is_Valid_Equality_Type -- ---------------------------- function Is_Valid_Equality_Type (T : Entity_Id; Anon_Access : Boolean) return Boolean is begin -- The operation must be performed in a context where the operators -- of the base type are visible. Deal with special types used with -- access types before type resolution is done. if Ekind (T) = E_Access_Attribute_Type or else (Ekind (T) in E_Access_Subprogram_Type | E_Access_Protected_Subprogram_Type and then Ekind (Designated_Type (T)) /= E_Subprogram_Type) or else Is_Visible_Operator (N, Base_Type (T)) then null; -- AI95-0230: Keep restriction imposed by Ada 83 and 95, do not allow -- anonymous access types in universal_access equality operators. elsif Anon_Access then if Ada_Version < Ada_2005 then return False; end if; -- Save candidate type for subsequent error message, if any else if Valid_Equality_Arg (T) then Candidate_Type := T; end if; return False; end if; -- For the use of a "/=" operator on a tagged type, several possible -- interpretations of equality need to be considered, we don't want -- the default inequality declared in Standard to be chosen, and the -- "/=" operator will be rewritten as a negation of "=" (see the end -- of Analyze_Comparison_Equality_Op). This ensures the rewriting -- occurs during analysis rather than being delayed until expansion. -- Note that, if the node is N_Op_Ne but Op_Id is Name_Op_Eq, then we -- still proceed with the interpretation, because this indicates -- the aforementioned rewriting case where the interpretation to be -- considered is actually that of the "=" operator. if Nkind (N) = N_Op_Ne and then Op_Name /= Name_Op_Eq and then Is_Tagged_Type (T) then return False; -- Defer to the common implementation for the rest else return Valid_Equality_Arg (T); end if; end Is_Valid_Equality_Type; ------------------- -- Is_Valid_Pair -- ------------------- function Is_Valid_Pair (T1, T2 : Entity_Id) return Boolean is begin if Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then declare Anon_Access : constant Boolean := Is_Anonymous_Access_Type (T1) or else Is_Anonymous_Access_Type (T2); -- RM 4.5.2(9.1/2): At least one of the operands of an equality -- operator for universal_access shall be of specific anonymous -- access type. begin if not Is_Valid_Equality_Type (T1, Anon_Access) or else not Is_Valid_Equality_Type (T2, Anon_Access) then return False; end if; end; else if not Is_Valid_Comparison_Type (T1) or else not Is_Valid_Comparison_Type (T2) then return False; end if; end if; return Covers (T1 => T1, T2 => T2) or else Covers (T1 => T2, T2 => T1) or else Is_User_Defined_Literal (L, T2) or else Is_User_Defined_Literal (R, T1); end Is_Valid_Pair; -- Local variables I : Interp_Index; It : Interp; L_Typ : Entity_Id; R_Typ : Entity_Id; T : Entity_Id; Valid_I : Interp_Index; -- Start of processing for Find_Comparison_Equality_Types begin -- Loop through the interpretations of the left operand if not Is_Overloaded (L) then T := Try_Left_Interp (Etype (L)); if Present (T) then Set_Etype (R, T); Add_One_Interp (N, Op_Id, Op_Typ, Find_Unique_Type (L, R)); end if; else L_Typ := Empty; R_Typ := Empty; Valid_I := 0; Get_First_Interp (L, I, It); while Present (It.Typ) loop T := Try_Left_Interp (It.Typ); if Present (T) then -- If several interpretations are possible, disambiguate if Present (L_Typ) and then Base_Type (It.Typ) /= Base_Type (L_Typ) then It := Disambiguate (L, Valid_I, I, Any_Type); if It = No_Interp then L_Typ := Any_Type; R_Typ := T; exit; end if; else Valid_I := I; end if; L_Typ := It.Typ; R_Typ := T; end if; Get_Next_Interp (I, It); end loop; if Present (L_Typ) then Set_Etype (L, L_Typ); Set_Etype (R, R_Typ); Add_One_Interp (N, Op_Id, Op_Typ, Find_Unique_Type (L, R)); end if; end if; end Find_Comparison_Equality_Types; ------------------------------ -- Find_Concatenation_Types -- ------------------------------ procedure Find_Concatenation_Types (L, R : Node_Id; Op_Id : Entity_Id; N : Node_Id) is Is_String : constant Boolean := Nkind (L) = N_String_Literal or else Nkind (R) = N_String_Literal; Op_Type : constant Entity_Id := Etype (Op_Id); begin if Is_Array_Type (Op_Type) -- Small but very effective optimization: if at least one operand is a -- string literal, then the type of the operator must be either array -- of characters or array of strings. and then (not Is_String or else Is_Character_Type (Component_Type (Op_Type)) or else Is_String_Type (Component_Type (Op_Type))) and then not Is_Limited_Type (Op_Type) and then (Has_Compatible_Type (L, Op_Type) or else Has_Compatible_Type (L, Component_Type (Op_Type))) and then (Has_Compatible_Type (R, Op_Type) or else Has_Compatible_Type (R, Component_Type (Op_Type))) then Add_One_Interp (N, Op_Id, Op_Type); end if; end Find_Concatenation_Types; ------------------------- -- Find_Negation_Types -- ------------------------- procedure Find_Negation_Types (R : Node_Id; Op_Id : Entity_Id; N : Node_Id) is Index : Interp_Index; It : Interp; begin if not Is_Overloaded (R) then if Etype (R) = Universal_Integer then Add_One_Interp (N, Op_Id, Any_Modular); elsif Valid_Boolean_Arg (Etype (R)) then Add_One_Interp (N, Op_Id, Etype (R)); end if; else Get_First_Interp (R, Index, It); while Present (It.Typ) loop if Valid_Boolean_Arg (It.Typ) then Add_One_Interp (N, Op_Id, It.Typ); end if; Get_Next_Interp (Index, It); end loop; end if; end Find_Negation_Types; ------------------------------ -- Find_Primitive_Operation -- ------------------------------ function Find_Primitive_Operation (N : Node_Id) return Boolean is Obj : constant Node_Id := Prefix (N); Op : constant Node_Id := Selector_Name (N); Prim : Elmt_Id; Prims : Elist_Id; Typ : Entity_Id; begin Set_Etype (Op, Any_Type); if Is_Access_Type (Etype (Obj)) then Typ := Designated_Type (Etype (Obj)); else Typ := Etype (Obj); end if; if Is_Class_Wide_Type (Typ) then Typ := Root_Type (Typ); end if; Prims := Primitive_Operations (Typ); Prim := First_Elmt (Prims); while Present (Prim) loop if Chars (Node (Prim)) = Chars (Op) then Add_One_Interp (Op, Node (Prim), Etype (Node (Prim))); Set_Etype (N, Etype (Node (Prim))); end if; Next_Elmt (Prim); end loop; -- Now look for class-wide operations of the type or any of its -- ancestors by iterating over the homonyms of the selector. declare Cls_Type : constant Entity_Id := Class_Wide_Type (Typ); Hom : Entity_Id; begin Hom := Current_Entity (Op); while Present (Hom) loop if (Ekind (Hom) = E_Procedure or else Ekind (Hom) = E_Function) and then Scope (Hom) = Scope (Typ) and then Present (First_Formal (Hom)) and then (Base_Type (Etype (First_Formal (Hom))) = Cls_Type or else (Is_Access_Type (Etype (First_Formal (Hom))) and then Ekind (Etype (First_Formal (Hom))) = E_Anonymous_Access_Type and then Base_Type (Designated_Type (Etype (First_Formal (Hom)))) = Cls_Type)) then Add_One_Interp (Op, Hom, Etype (Hom)); Set_Etype (N, Etype (Hom)); end if; Hom := Homonym (Hom); end loop; end; return Etype (Op) /= Any_Type; end Find_Primitive_Operation; ---------------------- -- Find_Unary_Types -- ---------------------- procedure Find_Unary_Types (R : Node_Id; Op_Id : Entity_Id; N : Node_Id) is Index : Interp_Index; It : Interp; begin if not Is_Overloaded (R) then if Is_Numeric_Type (Etype (R)) then -- In an instance a generic actual may be a numeric type even if -- the formal in the generic unit was not. In that case, the -- predefined operator was not a possible interpretation in the -- generic, and cannot be one in the instance, unless the operator -- is an actual of an instance. if In_Instance and then not Is_Numeric_Type (Corresponding_Generic_Type (Etype (R))) then null; else Add_One_Interp (N, Op_Id, Base_Type (Etype (R))); end if; end if; else Get_First_Interp (R, Index, It); while Present (It.Typ) loop if Is_Numeric_Type (It.Typ) then if In_Instance and then not Is_Numeric_Type (Corresponding_Generic_Type (Etype (It.Typ))) then null; elsif Is_Effectively_Visible_Operator (N, Base_Type (It.Typ)) then Add_One_Interp (N, Op_Id, Base_Type (It.Typ)); end if; end if; Get_Next_Interp (Index, It); end loop; end if; end Find_Unary_Types; ------------------ -- Junk_Operand -- ------------------ function Junk_Operand (N : Node_Id) return Boolean is Enode : Node_Id; begin if Error_Posted (N) then return False; end if; -- Get entity to be tested if Is_Entity_Name (N) and then Present (Entity (N)) then Enode := N; -- An odd case, a procedure name gets converted to a very peculiar -- function call, and here is where we detect this happening. elsif Nkind (N) = N_Function_Call and then Is_Entity_Name (Name (N)) and then Present (Entity (Name (N))) then Enode := Name (N); -- Another odd case, there are at least some cases of selected -- components where the selected component is not marked as having -- an entity, even though the selector does have an entity elsif Nkind (N) = N_Selected_Component and then Present (Entity (Selector_Name (N))) then Enode := Selector_Name (N); else return False; end if; -- Now test the entity we got to see if it is a bad case case Ekind (Entity (Enode)) is when E_Package => Error_Msg_N ("package name cannot be used as operand", Enode); when Generic_Unit_Kind => Error_Msg_N ("generic unit name cannot be used as operand", Enode); when Type_Kind => Error_Msg_N ("subtype name cannot be used as operand", Enode); when Entry_Kind => Error_Msg_N ("entry name cannot be used as operand", Enode); when E_Procedure => Error_Msg_N ("procedure name cannot be used as operand", Enode); when E_Exception => Error_Msg_N ("exception name cannot be used as operand", Enode); when E_Block | E_Label | E_Loop => Error_Msg_N ("label name cannot be used as operand", Enode); when others => return False; end case; return True; end Junk_Operand; -------------------- -- Operator_Check -- -------------------- procedure Operator_Check (N : Node_Id) is begin Remove_Abstract_Operations (N); -- Test for case of no interpretation found for operator if Etype (N) = Any_Type then declare L : constant Node_Id := (if Nkind (N) in N_Binary_Op then Left_Opnd (N) else Empty); R : constant Node_Id := Right_Opnd (N); begin -- If either operand has no type, then don't complain further, -- since this simply means that we have a propagated error. if R = Error or else Etype (R) = Any_Type or else (Nkind (N) in N_Binary_Op and then Etype (L) = Any_Type) then -- For the rather unusual case where one of the operands is -- a Raise_Expression, whose initial type is Any_Type, use -- the type of the other operand. if Nkind (L) = N_Raise_Expression then Set_Etype (L, Etype (R)); Set_Etype (N, Etype (R)); elsif Nkind (R) = N_Raise_Expression then Set_Etype (R, Etype (L)); Set_Etype (N, Etype (L)); end if; return; -- We explicitly check for the case of concatenation of component -- with component to avoid reporting spurious matching array types -- that might happen to be lurking in distant packages (such as -- run-time packages). This also prevents inconsistencies in the -- messages for certain ACVC B tests, which can vary depending on -- types declared in run-time interfaces. Another improvement when -- aggregates are present is to look for a well-typed operand. elsif Present (Candidate_Type) and then (Nkind (N) /= N_Op_Concat or else Is_Array_Type (Etype (L)) or else Is_Array_Type (Etype (R))) then if Nkind (N) = N_Op_Concat then if Etype (L) /= Any_Composite and then Is_Array_Type (Etype (L)) then Candidate_Type := Etype (L); elsif Etype (R) /= Any_Composite and then Is_Array_Type (Etype (R)) then Candidate_Type := Etype (R); end if; end if; Error_Msg_NE -- CODEFIX ("operator for} is not directly visible!", N, First_Subtype (Candidate_Type)); declare U : constant Node_Id := Cunit (Get_Source_Unit (Candidate_Type)); begin if Unit_Is_Visible (U) then Error_Msg_N -- CODEFIX ("use clause would make operation legal!", N); else Error_Msg_NE -- CODEFIX ("add with_clause and use_clause for&!", N, Defining_Entity (Unit (U))); end if; end; return; -- If either operand is a junk operand (e.g. package name), then -- post appropriate error messages, but do not complain further. -- Note that the use of OR in this test instead of OR ELSE is -- quite deliberate, we may as well check both operands in the -- binary operator case. elsif Junk_Operand (R) or -- really mean OR here and not OR ELSE, see above (Nkind (N) in N_Binary_Op and then Junk_Operand (L)) then return; -- The handling of user-defined literals is deferred to the second -- pass of resolution. elsif Has_Possible_User_Defined_Literal (N) then return; -- If we have a logical operator, one of whose operands is -- Boolean, then we know that the other operand cannot resolve to -- Boolean (since we got no interpretations), but in that case we -- pretty much know that the other operand should be Boolean, so -- resolve it that way (generating an error). elsif Nkind (N) in N_Op_And | N_Op_Or | N_Op_Xor then if Etype (L) = Standard_Boolean then Resolve (R, Standard_Boolean); return; elsif Etype (R) = Standard_Boolean then Resolve (L, Standard_Boolean); return; end if; -- For an arithmetic operator or comparison operator, if one -- of the operands is numeric, then we know the other operand -- is not the same numeric type. If it is a non-numeric type, -- then probably it is intended to match the other operand. elsif Nkind (N) in N_Op_Add | N_Op_Divide | N_Op_Ge | N_Op_Gt | N_Op_Le | N_Op_Lt | N_Op_Mod | N_Op_Multiply | N_Op_Rem | N_Op_Subtract then -- If Allow_Integer_Address is active, check whether the -- operation becomes legal after converting an operand. if Is_Numeric_Type (Etype (L)) and then not Is_Numeric_Type (Etype (R)) then if Address_Integer_Convert_OK (Etype (R), Etype (L)) then Rewrite (L, Unchecked_Convert_To ( Standard_Address, Relocate_Node (L))); Rewrite (R, Unchecked_Convert_To ( Standard_Address, Relocate_Node (R))); if Nkind (N) in N_Op_Ge | N_Op_Gt | N_Op_Le | N_Op_Lt then Analyze_Comparison_Equality_Op (N); else Analyze_Arithmetic_Op (N); end if; else Resolve (R, Etype (L)); end if; return; elsif Is_Numeric_Type (Etype (R)) and then not Is_Numeric_Type (Etype (L)) then if Address_Integer_Convert_OK (Etype (L), Etype (R)) then Rewrite (L, Unchecked_Convert_To ( Standard_Address, Relocate_Node (L))); Rewrite (R, Unchecked_Convert_To ( Standard_Address, Relocate_Node (R))); if Nkind (N) in N_Op_Ge | N_Op_Gt | N_Op_Le | N_Op_Lt then Analyze_Comparison_Equality_Op (N); else Analyze_Arithmetic_Op (N); end if; return; else Resolve (L, Etype (R)); end if; return; elsif Allow_Integer_Address and then Is_Descendant_Of_Address (Etype (L)) and then Is_Descendant_Of_Address (Etype (R)) and then not Error_Posted (N) then declare Addr_Type : constant Entity_Id := Etype (L); begin Rewrite (L, Unchecked_Convert_To ( Standard_Address, Relocate_Node (L))); Rewrite (R, Unchecked_Convert_To ( Standard_Address, Relocate_Node (R))); if Nkind (N) in N_Op_Ge | N_Op_Gt | N_Op_Le | N_Op_Lt then Analyze_Comparison_Equality_Op (N); else Analyze_Arithmetic_Op (N); end if; -- If this is an operand in an enclosing arithmetic -- operation, Convert the result as an address so that -- arithmetic folding of address can continue. if Nkind (Parent (N)) in N_Op then Rewrite (N, Unchecked_Convert_To (Addr_Type, Relocate_Node (N))); end if; return; end; -- Under relaxed RM semantics silently replace occurrences of -- null by System.Address_Null. elsif Null_To_Null_Address_Convert_OK (N) then Replace_Null_By_Null_Address (N); if Nkind (N) in N_Op_Ge | N_Op_Gt | N_Op_Le | N_Op_Lt then Analyze_Comparison_Equality_Op (N); else Analyze_Arithmetic_Op (N); end if; return; end if; -- Comparisons on A'Access are common enough to deserve a -- special message. elsif Nkind (N) in N_Op_Eq | N_Op_Ne and then Ekind (Etype (L)) = E_Access_Attribute_Type and then Ekind (Etype (R)) = E_Access_Attribute_Type then Error_Msg_N ("two access attributes cannot be compared directly", N); Error_Msg_N ("\use qualified expression for one of the operands", N); return; -- Another one for C programmers elsif Nkind (N) = N_Op_Concat and then Valid_Boolean_Arg (Etype (L)) and then Valid_Boolean_Arg (Etype (R)) then Error_Msg_N ("invalid operands for concatenation", N); Error_Msg_N -- CODEFIX ("\maybe AND was meant", N); return; -- A special case for comparison of access parameter with null elsif Nkind (N) = N_Op_Eq and then Is_Entity_Name (L) and then Nkind (Parent (Entity (L))) = N_Parameter_Specification and then Nkind (Parameter_Type (Parent (Entity (L)))) = N_Access_Definition and then Nkind (R) = N_Null then Error_Msg_N ("access parameter is not allowed to be null", L); Error_Msg_N ("\(call would raise Constraint_Error)", L); return; -- Another special case for exponentiation, where the right -- operand must be Natural, independently of the base. elsif Nkind (N) = N_Op_Expon and then Is_Numeric_Type (Etype (L)) and then not Is_Overloaded (R) and then First_Subtype (Base_Type (Etype (R))) /= Standard_Integer and then Base_Type (Etype (R)) /= Universal_Integer then if Ada_Version >= Ada_2012 and then Has_Dimension_System (Etype (L)) then Error_Msg_NE ("exponent for dimensioned type must be a rational" & ", found}", R, Etype (R)); else Error_Msg_NE ("exponent must be of type Natural, found}", R, Etype (R)); end if; return; elsif Nkind (N) in N_Op_Eq | N_Op_Ne then if Address_Integer_Convert_OK (Etype (R), Etype (L)) then Rewrite (L, Unchecked_Convert_To ( Standard_Address, Relocate_Node (L))); Rewrite (R, Unchecked_Convert_To ( Standard_Address, Relocate_Node (R))); Analyze_Comparison_Equality_Op (N); return; -- Under relaxed RM semantics silently replace occurrences of -- null by System.Address_Null. elsif Null_To_Null_Address_Convert_OK (N) then Replace_Null_By_Null_Address (N); Analyze_Comparison_Equality_Op (N); return; end if; end if; -- If we fall through then just give general message Unresolved_Operator (N); end; end if; end Operator_Check; --------------------------------------- -- Has_Possible_User_Defined_Literal -- --------------------------------------- function Has_Possible_User_Defined_Literal (N : Node_Id) return Boolean is R : constant Node_Id := Right_Opnd (N); procedure Check_Literal_Opnd (Opnd : Node_Id); -- If an operand is a literal to which an aspect may apply, -- add the corresponding type to operator node. ------------------------ -- Check_Literal_Opnd -- ------------------------ procedure Check_Literal_Opnd (Opnd : Node_Id) is begin if Nkind (Opnd) in N_Numeric_Or_String_Literal or else (Is_Entity_Name (Opnd) and then Present (Entity (Opnd)) and then Is_Named_Number (Entity (Opnd))) then Add_One_Interp (N, Etype (Opnd), Etype (Opnd)); end if; end Check_Literal_Opnd; -- Start of processing for Has_Possible_User_Defined_Literal begin if Ada_Version < Ada_2022 then return False; end if; Check_Literal_Opnd (R); -- Check left operand only if right one did not provide a -- possible interpretation. Note that literal types are not -- overloadable, in the sense that there is no overloadable -- entity name whose several interpretations can be used to -- indicate possible resulting types, so there is no way to -- provide more than one interpretation to the operator node. -- The choice of one operand over the other is arbitrary at -- this point, and may lead to spurious resolution when both -- operands are literals of different kinds, but the second -- pass of resolution will examine anew both operands to -- determine whether a user-defined literal may apply to -- either or both. if Nkind (N) in N_Binary_Op and then Etype (N) = Any_Type then Check_Literal_Opnd (Left_Opnd (N)); end if; return Etype (N) /= Any_Type; end Has_Possible_User_Defined_Literal; ----------------------------------------------- -- Nondispatching_Call_To_Abstract_Operation -- ----------------------------------------------- procedure Nondispatching_Call_To_Abstract_Operation (N : Node_Id; Abstract_Op : Entity_Id) is Typ : constant Entity_Id := Etype (N); begin -- In an instance body, this is a runtime check, but one we know will -- fail, so give an appropriate warning. As usual this kind of warning -- is an error in SPARK mode. Error_Msg_Sloc := Sloc (Abstract_Op); if In_Instance_Body and then SPARK_Mode /= On then Error_Msg_NE ("??cannot call abstract operation& declared#", N, Abstract_Op); Error_Msg_N ("\Program_Error [??", N); Rewrite (N, Make_Raise_Program_Error (Sloc (N), Reason => PE_Explicit_Raise)); Analyze (N); Set_Etype (N, Typ); else Error_Msg_NE ("cannot call abstract operation& declared#", N, Abstract_Op); Set_Etype (N, Any_Type); end if; end Nondispatching_Call_To_Abstract_Operation; ---------------------------------------------- -- Possible_Type_For_Conditional_Expression -- ---------------------------------------------- function Possible_Type_For_Conditional_Expression (T1, T2 : Entity_Id) return Entity_Id is function Is_Access_Protected_Subprogram_Attribute (T : Entity_Id) return Boolean; -- Return true if T is the type of an access-to-protected-subprogram -- attribute. function Is_Access_Subprogram_Attribute (T : Entity_Id) return Boolean; -- Return true if T is the type of an access-to-subprogram attribute ---------------------------------------------- -- Is_Access_Protected_Subprogram_Attribute -- ---------------------------------------------- function Is_Access_Protected_Subprogram_Attribute (T : Entity_Id) return Boolean is begin return Ekind (T) = E_Access_Protected_Subprogram_Type and then Ekind (Designated_Type (T)) /= E_Subprogram_Type; end Is_Access_Protected_Subprogram_Attribute; ------------------------------------ -- Is_Access_Subprogram_Attribute -- ------------------------------------ function Is_Access_Subprogram_Attribute (T : Entity_Id) return Boolean is begin return Ekind (T) = E_Access_Subprogram_Type and then Ekind (Designated_Type (T)) /= E_Subprogram_Type; end Is_Access_Subprogram_Attribute; -- Start of processing for Possible_Type_For_Conditional_Expression begin -- If both types are those of similar access attributes or allocators, -- pick one of them, for example the first. if Ekind (T1) in E_Access_Attribute_Type | E_Allocator_Type and then Ekind (T2) in E_Access_Attribute_Type | E_Allocator_Type then return T1; elsif Is_Access_Subprogram_Attribute (T1) and then Is_Access_Subprogram_Attribute (T2) and then Subtype_Conformant (Designated_Type (T1), Designated_Type (T2)) then return T1; elsif Is_Access_Protected_Subprogram_Attribute (T1) and then Is_Access_Protected_Subprogram_Attribute (T2) and then Subtype_Conformant (Designated_Type (T1), Designated_Type (T2)) then return T1; -- The other case to be considered is a pair of tagged types elsif Is_Tagged_Type (T1) and then Is_Tagged_Type (T2) then -- Covers performs the same checks when T1 or T2 are a CW type, so -- we don't need to do them again here. if not Is_Class_Wide_Type (T1) and then Is_Ancestor (T1, T2) then return T1; elsif not Is_Class_Wide_Type (T2) and then Is_Ancestor (T2, T1) then return T2; -- Neither type is an ancestor of the other, but they may have one in -- common, so we pick the first type as above. We could perform here -- the computation of the nearest common ancestors of T1 and T2, but -- this would require a significant amount of work and the practical -- benefit would very likely be negligible. else return T1; end if; -- Otherwise no type is possible else return Empty; end if; end Possible_Type_For_Conditional_Expression; -------------------------------- -- Remove_Abstract_Operations -- -------------------------------- procedure Remove_Abstract_Operations (N : Node_Id) is Abstract_Op : Entity_Id := Empty; Address_Descendant : Boolean := False; I : Interp_Index; It : Interp; -- AI-310: If overloaded, remove abstract non-dispatching operations. We -- activate this if either extensions are enabled, or if the abstract -- operation in question comes from a predefined file. This latter test -- allows us to use abstract to make operations invisible to users. In -- particular, if type Address is non-private and abstract subprograms -- are used to hide its operators, they will be truly hidden. type Operand_Position is (First_Op, Second_Op); Univ_Type : constant Entity_Id := Universal_Interpretation (N); procedure Remove_Address_Interpretations (Op : Operand_Position); -- Ambiguities may arise when the operands are literal and the address -- operations in s-auxdec are visible. In that case, remove the -- interpretation of a literal as Address, to retain the semantics -- of Address as a private type. ------------------------------------ -- Remove_Address_Interpretations -- ------------------------------------ procedure Remove_Address_Interpretations (Op : Operand_Position) is Formal : Entity_Id; begin if Is_Overloaded (N) then Get_First_Interp (N, I, It); while Present (It.Nam) loop Formal := First_Entity (It.Nam); if Op = Second_Op then Next_Entity (Formal); end if; if Is_Descendant_Of_Address (Etype (Formal)) then Address_Descendant := True; Remove_Interp (I); end if; Get_Next_Interp (I, It); end loop; end if; end Remove_Address_Interpretations; -- Start of processing for Remove_Abstract_Operations begin if Is_Overloaded (N) then if Debug_Flag_V then Write_Line ("Remove_Abstract_Operations: "); Write_Overloads (N); end if; Get_First_Interp (N, I, It); while Present (It.Nam) loop if Is_Overloadable (It.Nam) and then Is_Abstract_Subprogram (It.Nam) and then not Is_Dispatching_Operation (It.Nam) then Abstract_Op := It.Nam; if Is_Descendant_Of_Address (It.Typ) then Address_Descendant := True; Remove_Interp (I); exit; -- In Ada 2005, this operation does not participate in overload -- resolution. If the operation is defined in a predefined -- unit, it is one of the operations declared abstract in some -- variants of System, and it must be removed as well. elsif Ada_Version >= Ada_2005 or else In_Predefined_Unit (It.Nam) then Remove_Interp (I); exit; end if; end if; Get_Next_Interp (I, It); end loop; if No (Abstract_Op) then -- If some interpretation yields an integer type, it is still -- possible that there are address interpretations. Remove them -- if one operand is a literal, to avoid spurious ambiguities -- on systems where Address is a visible integer type. if Is_Overloaded (N) and then Nkind (N) in N_Op and then Is_Integer_Type (Etype (N)) then if Nkind (N) in N_Binary_Op then if Nkind (Right_Opnd (N)) = N_Integer_Literal then Remove_Address_Interpretations (Second_Op); elsif Nkind (Left_Opnd (N)) = N_Integer_Literal then Remove_Address_Interpretations (First_Op); end if; end if; end if; elsif Nkind (N) in N_Op then -- Remove interpretations that treat literals as addresses. This -- is never appropriate, even when Address is defined as a visible -- Integer type. The reason is that we would really prefer Address -- to behave as a private type, even in this case. If Address is a -- visible integer type, we get lots of overload ambiguities. if Nkind (N) in N_Binary_Op then declare U1 : constant Boolean := Present (Universal_Interpretation (Right_Opnd (N))); U2 : constant Boolean := Present (Universal_Interpretation (Left_Opnd (N))); begin if U1 then Remove_Address_Interpretations (Second_Op); end if; if U2 then Remove_Address_Interpretations (First_Op); end if; if not (U1 and U2) then -- Remove corresponding predefined operator, which is -- always added to the overload set. Get_First_Interp (N, I, It); while Present (It.Nam) loop if Scope (It.Nam) = Standard_Standard and then Base_Type (It.Typ) = Base_Type (Etype (Abstract_Op)) then Remove_Interp (I); end if; Get_Next_Interp (I, It); end loop; elsif Is_Overloaded (N) and then Present (Univ_Type) then -- If both operands have a universal interpretation, -- it is still necessary to remove interpretations that -- yield Address. Any remaining ambiguities will be -- removed in Disambiguate. Get_First_Interp (N, I, It); while Present (It.Nam) loop if Is_Descendant_Of_Address (It.Typ) then Remove_Interp (I); elsif not Is_Type (It.Nam) then Set_Entity (N, It.Nam); end if; Get_Next_Interp (I, It); end loop; end if; end; end if; elsif Nkind (N) = N_Function_Call and then (Nkind (Name (N)) = N_Operator_Symbol or else (Nkind (Name (N)) = N_Expanded_Name and then Nkind (Selector_Name (Name (N))) = N_Operator_Symbol)) then declare Arg1 : constant Node_Id := First (Parameter_Associations (N)); U1 : constant Boolean := Present (Universal_Interpretation (Arg1)); U2 : constant Boolean := Present (Next (Arg1)) and then Present (Universal_Interpretation (Next (Arg1))); begin if U1 then Remove_Address_Interpretations (First_Op); end if; if U2 then Remove_Address_Interpretations (Second_Op); end if; if not (U1 and U2) then Get_First_Interp (N, I, It); while Present (It.Nam) loop if Scope (It.Nam) = Standard_Standard and then It.Typ = Base_Type (Etype (Abstract_Op)) then Remove_Interp (I); end if; Get_Next_Interp (I, It); end loop; end if; end; end if; -- If the removal has left no valid interpretations, emit an error -- message now and label node as illegal. if Present (Abstract_Op) then Get_First_Interp (N, I, It); if No (It.Nam) then -- Removal of abstract operation left no viable candidate Nondispatching_Call_To_Abstract_Operation (N, Abstract_Op); -- In Ada 2005, an abstract operation may disable predefined -- operators. Since the context is not yet known, we mark the -- predefined operators as potentially hidden. Do not include -- predefined operators when addresses are involved since this -- case is handled separately. elsif Ada_Version >= Ada_2005 and then not Address_Descendant then while Present (It.Nam) loop if Is_Numeric_Type (It.Typ) and then Scope (It.Typ) = Standard_Standard and then Ekind (It.Nam) = E_Operator then Set_Abstract_Op (I, Abstract_Op); end if; Get_Next_Interp (I, It); end loop; end if; end if; if Debug_Flag_V then Write_Line ("Remove_Abstract_Operations done: "); Write_Overloads (N); end if; end if; end Remove_Abstract_Operations; ---------------------------- -- Try_Container_Indexing -- ---------------------------- function Try_Container_Indexing (N : Node_Id; Prefix : Node_Id; Exprs : List_Id) return Boolean is Pref_Typ : Entity_Id := Etype (Prefix); function Constant_Indexing_OK return Boolean; -- Constant_Indexing is legal if there is no Variable_Indexing defined -- for the type, or else node not a target of assignment, or an actual -- for an IN OUT or OUT formal (RM 4.1.6 (11)). function Expr_Matches_In_Formal (Subp : Entity_Id; Par : Node_Id) return Boolean; -- Find formal corresponding to given indexed component that is an -- actual in a call. Note that the enclosing subprogram call has not -- been analyzed yet, and the parameter list is not normalized, so -- that if the argument is a parameter association we must match it -- by name and not by position. function Find_Indexing_Operations (T : Entity_Id; Nam : Name_Id; Is_Constant : Boolean) return Node_Id; -- Return a reference to the primitive operation of type T denoted by -- name Nam. If the operation is overloaded, the reference carries all -- interpretations. Flag Is_Constant should be set when the context is -- constant indexing. -------------------------- -- Constant_Indexing_OK -- -------------------------- function Constant_Indexing_OK return Boolean is Par : Node_Id; begin if No (Find_Value_Of_Aspect (Pref_Typ, Aspect_Variable_Indexing)) then return True; elsif not Is_Variable (Prefix) then return True; end if; Par := N; while Present (Par) loop if Nkind (Parent (Par)) = N_Assignment_Statement and then Par = Name (Parent (Par)) then return False; -- The call may be overloaded, in which case we assume that its -- resolution does not depend on the type of the parameter that -- includes the indexing operation. elsif Nkind (Parent (Par)) in N_Subprogram_Call then if not Is_Entity_Name (Name (Parent (Par))) then -- ??? We don't know what to do with an N_Selected_Component -- node for a prefixed-notation call to AA.BB where AA's -- type is known, but BB has not yet been resolved. In that -- case, the preceding Is_Entity_Name call returns False. -- Incorrectly returning False here will usually work -- better than incorrectly returning True, so that's what -- we do for now. return False; end if; declare Proc : Entity_Id; begin -- We should look for an interpretation with the proper -- number of formals, and determine whether it is an -- In_Parameter, but for now we examine the formal that -- corresponds to the indexing, and assume that variable -- indexing is required if some interpretation has an -- assignable formal at that position. Still does not -- cover the most complex cases ??? if Is_Overloaded (Name (Parent (Par))) then declare Proc : constant Node_Id := Name (Parent (Par)); I : Interp_Index; It : Interp; begin Get_First_Interp (Proc, I, It); while Present (It.Nam) loop if not Expr_Matches_In_Formal (It.Nam, Par) then return False; end if; Get_Next_Interp (I, It); end loop; end; -- All interpretations have a matching in-mode formal return True; else Proc := Entity (Name (Parent (Par))); -- If this is an indirect call, get formals from -- designated type. if Is_Access_Subprogram_Type (Etype (Proc)) then Proc := Designated_Type (Etype (Proc)); end if; end if; return Expr_Matches_In_Formal (Proc, Par); end; elsif Nkind (Parent (Par)) = N_Object_Renaming_Declaration then return False; -- If the indexed component is a prefix it may be the first actual -- of a prefixed call. Retrieve the called entity, if any, and -- check its first formal. Determine if the context is a procedure -- or function call. elsif Nkind (Parent (Par)) = N_Selected_Component then declare Sel : constant Node_Id := Selector_Name (Parent (Par)); Nam : constant Entity_Id := Current_Entity (Sel); begin if Present (Nam) and then Is_Overloadable (Nam) then if Nkind (Parent (Parent (Par))) = N_Procedure_Call_Statement then return False; elsif Ekind (Nam) = E_Function and then Present (First_Formal (Nam)) then return Ekind (First_Formal (Nam)) = E_In_Parameter; end if; end if; end; elsif Nkind (Par) in N_Op then return True; end if; Par := Parent (Par); end loop; -- In all other cases, constant indexing is legal return True; end Constant_Indexing_OK; ---------------------------- -- Expr_Matches_In_Formal -- ---------------------------- function Expr_Matches_In_Formal (Subp : Entity_Id; Par : Node_Id) return Boolean is Actual : Node_Id; Formal : Node_Id; begin Formal := First_Formal (Subp); Actual := First (Parameter_Associations ((Parent (Par)))); if Nkind (Par) /= N_Parameter_Association then -- Match by position while Present (Actual) and then Present (Formal) loop exit when Actual = Par; Next (Actual); if Present (Formal) then Next_Formal (Formal); -- Otherwise this is a parameter mismatch, the error is -- reported elsewhere, or else variable indexing is implied. else return False; end if; end loop; else -- Match by name while Present (Formal) loop exit when Chars (Formal) = Chars (Selector_Name (Par)); Next_Formal (Formal); if No (Formal) then return False; end if; end loop; end if; return Present (Formal) and then Ekind (Formal) = E_In_Parameter; end Expr_Matches_In_Formal; ------------------------------ -- Find_Indexing_Operations -- ------------------------------ function Find_Indexing_Operations (T : Entity_Id; Nam : Name_Id; Is_Constant : Boolean) return Node_Id is procedure Inspect_Declarations (Typ : Entity_Id; Ref : in out Node_Id); -- Traverse the declarative list where type Typ resides and collect -- all suitable interpretations in node Ref. procedure Inspect_Primitives (Typ : Entity_Id; Ref : in out Node_Id); -- Traverse the list of primitive operations of type Typ and collect -- all suitable interpretations in node Ref. function Is_OK_Candidate (Subp_Id : Entity_Id; Typ : Entity_Id) return Boolean; -- Determine whether subprogram Subp_Id is a suitable indexing -- operation for type Typ. To qualify as such, the subprogram must -- be a function, have at least two parameters, and the type of the -- first parameter must be either Typ, or Typ'Class, or access [to -- constant] with designated type Typ or Typ'Class. procedure Record_Interp (Subp_Id : Entity_Id; Ref : in out Node_Id); -- Store subprogram Subp_Id as an interpretation in node Ref -------------------------- -- Inspect_Declarations -- -------------------------- procedure Inspect_Declarations (Typ : Entity_Id; Ref : in out Node_Id) is Typ_Decl : constant Node_Id := Declaration_Node (Typ); Decl : Node_Id; Subp_Id : Entity_Id; begin -- Ensure that the routine is not called with itypes, which lack a -- declarative node. pragma Assert (Present (Typ_Decl)); pragma Assert (Is_List_Member (Typ_Decl)); Decl := First (List_Containing (Typ_Decl)); while Present (Decl) loop if Nkind (Decl) = N_Subprogram_Declaration then Subp_Id := Defining_Entity (Decl); if Is_OK_Candidate (Subp_Id, Typ) then Record_Interp (Subp_Id, Ref); end if; end if; Next (Decl); end loop; end Inspect_Declarations; ------------------------ -- Inspect_Primitives -- ------------------------ procedure Inspect_Primitives (Typ : Entity_Id; Ref : in out Node_Id) is Prim_Elmt : Elmt_Id; Prim_Id : Entity_Id; begin Prim_Elmt := First_Elmt (Primitive_Operations (Typ)); while Present (Prim_Elmt) loop Prim_Id := Node (Prim_Elmt); if Is_OK_Candidate (Prim_Id, Typ) then Record_Interp (Prim_Id, Ref); end if; Next_Elmt (Prim_Elmt); end loop; end Inspect_Primitives; --------------------- -- Is_OK_Candidate -- --------------------- function Is_OK_Candidate (Subp_Id : Entity_Id; Typ : Entity_Id) return Boolean is Formal : Entity_Id; Formal_Typ : Entity_Id; Param_Typ : Node_Id; begin -- To classify as a suitable candidate, the subprogram must be a -- function whose name matches the argument of aspect Constant or -- Variable_Indexing. if Ekind (Subp_Id) = E_Function and then Chars (Subp_Id) = Nam then Formal := First_Formal (Subp_Id); -- The candidate requires at least two parameters if Present (Formal) and then Present (Next_Formal (Formal)) then Formal_Typ := Empty; Param_Typ := Parameter_Type (Parent (Formal)); -- Use the designated type when the first parameter is of an -- access type. if Nkind (Param_Typ) = N_Access_Definition and then Present (Subtype_Mark (Param_Typ)) then -- When the context is a constant indexing, the access -- definition must be access-to-constant. This does not -- apply to variable indexing. if not Is_Constant or else Constant_Present (Param_Typ) then Formal_Typ := Etype (Subtype_Mark (Param_Typ)); end if; -- Otherwise use the parameter type else Formal_Typ := Etype (Param_Typ); end if; if Present (Formal_Typ) then -- Use the specific type when the parameter type is -- class-wide. if Is_Class_Wide_Type (Formal_Typ) then Formal_Typ := Etype (Base_Type (Formal_Typ)); end if; -- Use the full view when the parameter type is private -- or incomplete. if Is_Incomplete_Or_Private_Type (Formal_Typ) and then Present (Full_View (Formal_Typ)) then Formal_Typ := Full_View (Formal_Typ); end if; -- The type of the first parameter must denote the type -- of the container or acts as its ancestor type. return Formal_Typ = Typ or else Is_Ancestor (Formal_Typ, Typ); end if; end if; end if; return False; end Is_OK_Candidate; ------------------- -- Record_Interp -- ------------------- procedure Record_Interp (Subp_Id : Entity_Id; Ref : in out Node_Id) is begin if Present (Ref) then Add_One_Interp (Ref, Subp_Id, Etype (Subp_Id)); -- Otherwise this is the first interpretation. Create a reference -- where all remaining interpretations will be collected. else Ref := New_Occurrence_Of (Subp_Id, Sloc (T)); end if; end Record_Interp; -- Local variables Ref : Node_Id; Typ : Entity_Id; -- Start of processing for Find_Indexing_Operations begin Typ := T; -- Use the specific type when the parameter type is class-wide if Is_Class_Wide_Type (Typ) then Typ := Root_Type (Typ); end if; Ref := Empty; Typ := Underlying_Type (Base_Type (Typ)); Inspect_Primitives (Typ, Ref); -- Now look for explicit declarations of an indexing operation. -- If the type is private the operation may be declared in the -- visible part that contains the partial view. if Is_Private_Type (T) then Inspect_Declarations (T, Ref); end if; Inspect_Declarations (Typ, Ref); return Ref; end Find_Indexing_Operations; -- Local variables Loc : constant Source_Ptr := Sloc (N); Assoc : List_Id; C_Type : Entity_Id; Func : Entity_Id; Func_Name : Node_Id; Indexing : Node_Id; Is_Constant_Indexing : Boolean := False; -- This flag reflects the nature of the container indexing. Note that -- the context may be suited for constant indexing, but the type may -- lack a Constant_Indexing annotation. -- Start of processing for Try_Container_Indexing begin -- Node may have been analyzed already when testing for a prefixed -- call, in which case do not redo analysis. if Present (Generalized_Indexing (N)) then return True; end if; -- An explicit dereference needs to be created in the case of a prefix -- that's an access. -- It seems that this should be done elsewhere, but not clear where that -- should happen. Normally Insert_Explicit_Dereference is called via -- Resolve_Implicit_Dereference, called from Resolve_Indexed_Component, -- but that won't be called in this case because we transform the -- indexing to a call. Resolve_Call.Check_Prefixed_Call takes care of -- implicit dereferencing and referencing on prefixed calls, but that -- would be too late, even if we expanded to a prefix call, because -- Process_Indexed_Component will flag an error before the resolution -- happens. ??? if Is_Access_Type (Pref_Typ) then Pref_Typ := Implicitly_Designated_Type (Pref_Typ); Insert_Explicit_Dereference (Prefix); Error_Msg_NW (Warn_On_Dereference, "?d?implicit dereference", N); end if; C_Type := Pref_Typ; -- If indexing a class-wide container, obtain indexing primitive from -- specific type. if Is_Class_Wide_Type (C_Type) then C_Type := Etype (Base_Type (C_Type)); end if; -- Check whether the type has a specified indexing aspect Func_Name := Empty; -- The context is suitable for constant indexing, so obtain the name of -- the indexing function from aspect Constant_Indexing. if Constant_Indexing_OK then Func_Name := Find_Value_Of_Aspect (Pref_Typ, Aspect_Constant_Indexing); end if; if Present (Func_Name) then Is_Constant_Indexing := True; -- Otherwise attempt variable indexing else Func_Name := Find_Value_Of_Aspect (Pref_Typ, Aspect_Variable_Indexing); end if; -- The type is not subject to either form of indexing, therefore the -- indexed component does not denote container indexing. If this is a -- true error, it is diagnosed by the caller. if No (Func_Name) then -- The prefix itself may be an indexing of a container. Rewrite it -- as such and retry. if Has_Implicit_Dereference (Pref_Typ) then Build_Explicit_Dereference (Prefix, Get_Reference_Discriminant (Pref_Typ)); return Try_Container_Indexing (N, Prefix, Exprs); -- Otherwise this is definitely not container indexing else return False; end if; -- If the container type is derived from another container type, the -- value of the inherited aspect is the Reference operation declared -- for the parent type. -- However, Reference is also a primitive operation of the type, and the -- inherited operation has a different signature. We retrieve the right -- ones (the function may be overloaded) from the list of primitive -- operations of the derived type. -- Note that predefined containers are typically all derived from one of -- the Controlled types. The code below is motivated by containers that -- are derived from other types with a Reference aspect. -- Note as well that we need to examine the base type, given that -- the container object may be a constrained subtype or itype that -- does not have an explicit declaration. elsif Is_Derived_Type (C_Type) and then Etype (First_Formal (Entity (Func_Name))) /= Pref_Typ then Func_Name := Find_Indexing_Operations (T => Base_Type (C_Type), Nam => Chars (Func_Name), Is_Constant => Is_Constant_Indexing); end if; Assoc := New_List (Relocate_Node (Prefix)); -- A generalized indexing may have nore than one index expression, so -- transfer all of them to the argument list to be used in the call. -- Note that there may be named associations, in which case the node -- was rewritten earlier as a call, and has been transformed back into -- an indexed expression to share the following processing. -- The generalized indexing node is the one on which analysis and -- resolution take place. Before expansion the original node is replaced -- with the generalized indexing node, which is a call, possibly with a -- dereference operation. -- Create argument list for function call that represents generalized -- indexing. Note that indices (i.e. actuals) may themselves be -- overloaded. declare Arg : Node_Id; New_Arg : Node_Id; begin Arg := First (Exprs); while Present (Arg) loop New_Arg := Relocate_Node (Arg); -- The arguments can be parameter associations, in which case the -- explicit actual parameter carries the overloadings. if Nkind (New_Arg) /= N_Parameter_Association then Save_Interps (Arg, New_Arg); end if; Append (New_Arg, Assoc); Next (Arg); end loop; end; if not Is_Overloaded (Func_Name) then Func := Entity (Func_Name); -- Can happen in case of e.g. cascaded errors if No (Func) then return False; end if; Indexing := Make_Function_Call (Loc, Name => New_Occurrence_Of (Func, Loc), Parameter_Associations => Assoc); Set_Parent (Indexing, Parent (N)); Set_Generalized_Indexing (N, Indexing); Analyze (Indexing); Set_Etype (N, Etype (Indexing)); -- If the return type of the indexing function is a reference type, -- add the dereference as a possible interpretation. Note that the -- indexing aspect may be a function that returns the element type -- with no intervening implicit dereference, and that the reference -- discriminant is not the first discriminant. if Has_Discriminants (Etype (Func)) then Check_Implicit_Dereference (N, Etype (Func)); end if; else -- If there are multiple indexing functions, build a function call -- and analyze it for each of the possible interpretations. Indexing := Make_Function_Call (Loc, Name => Make_Identifier (Loc, Chars (Func_Name)), Parameter_Associations => Assoc); Set_Parent (Indexing, Parent (N)); Set_Generalized_Indexing (N, Indexing); Set_Etype (N, Any_Type); Set_Etype (Name (Indexing), Any_Type); declare I : Interp_Index; It : Interp; Success : Boolean; begin Get_First_Interp (Func_Name, I, It); Set_Etype (Indexing, Any_Type); -- Analyze each candidate function with the given actuals while Present (It.Nam) loop Analyze_One_Call (Indexing, It.Nam, False, Success); Get_Next_Interp (I, It); end loop; -- If there are several successful candidates, resolution will -- be by result. Mark the interpretations of the function name -- itself. if Is_Overloaded (Indexing) then Get_First_Interp (Indexing, I, It); while Present (It.Nam) loop Add_One_Interp (Name (Indexing), It.Nam, It.Typ); Get_Next_Interp (I, It); end loop; else Set_Etype (Name (Indexing), Etype (Indexing)); end if; -- Now add the candidate interpretations to the indexing node -- itself, to be replaced later by the function call. if Is_Overloaded (Name (Indexing)) then Get_First_Interp (Name (Indexing), I, It); while Present (It.Nam) loop Add_One_Interp (N, It.Nam, It.Typ); -- Add dereference interpretation if the result type has -- implicit reference discriminants. if Has_Discriminants (Etype (It.Nam)) then Check_Implicit_Dereference (N, Etype (It.Nam)); end if; Get_Next_Interp (I, It); end loop; else Set_Etype (N, Etype (Name (Indexing))); if Has_Discriminants (Etype (N)) then Check_Implicit_Dereference (N, Etype (N)); end if; end if; end; end if; if Etype (Indexing) = Any_Type then Error_Msg_NE ("container cannot be indexed with&", N, Etype (First (Exprs))); Rewrite (N, New_Occurrence_Of (Any_Id, Loc)); end if; return True; end Try_Container_Indexing; ----------------------- -- Try_Indirect_Call -- ----------------------- function Try_Indirect_Call (N : Node_Id; Nam : Entity_Id; Typ : Entity_Id) return Boolean is Actual : Node_Id; Formal : Entity_Id; Call_OK : Boolean; pragma Warnings (Off, Call_OK); begin Normalize_Actuals (N, Designated_Type (Typ), False, Call_OK); Actual := First_Actual (N); Formal := First_Formal (Designated_Type (Typ)); while Present (Actual) and then Present (Formal) loop if not Has_Compatible_Type (Actual, Etype (Formal)) then return False; end if; Next (Actual); Next_Formal (Formal); end loop; if No (Actual) and then No (Formal) then Add_One_Interp (N, Nam, Etype (Designated_Type (Typ))); -- Nam is a candidate interpretation for the name in the call, -- if it is not an indirect call. if not Is_Type (Nam) and then Is_Entity_Name (Name (N)) then Set_Entity (Name (N), Nam); end if; return True; else return False; end if; end Try_Indirect_Call; ---------------------- -- Try_Indexed_Call -- ---------------------- function Try_Indexed_Call (N : Node_Id; Nam : Entity_Id; Typ : Entity_Id; Skip_First : Boolean) return Boolean is Loc : constant Source_Ptr := Sloc (N); Actuals : constant List_Id := Parameter_Associations (N); Actual : Node_Id; Index : Entity_Id; begin Actual := First (Actuals); -- If the call was originally written in prefix form, skip the first -- actual, which is obviously not defaulted. if Skip_First then Next (Actual); end if; Index := First_Index (Typ); while Present (Actual) and then Present (Index) loop -- If the parameter list has a named association, the expression -- is definitely a call and not an indexed component. if Nkind (Actual) = N_Parameter_Association then return False; end if; if Is_Entity_Name (Actual) and then Is_Type (Entity (Actual)) and then No (Next (Actual)) then -- A single actual that is a type name indicates a slice if the -- type is discrete, and an error otherwise. if Is_Discrete_Type (Entity (Actual)) then Rewrite (N, Make_Slice (Loc, Prefix => Make_Function_Call (Loc, Name => Relocate_Node (Name (N))), Discrete_Range => New_Occurrence_Of (Entity (Actual), Sloc (Actual)))); Analyze (N); else Error_Msg_N ("invalid use of type in expression", Actual); Set_Etype (N, Any_Type); end if; return True; elsif not Has_Compatible_Type (Actual, Etype (Index)) then return False; end if; Next (Actual); Next_Index (Index); end loop; if No (Actual) and then No (Index) then Add_One_Interp (N, Nam, Component_Type (Typ)); -- Nam is a candidate interpretation for the name in the call, -- if it is not an indirect call. if not Is_Type (Nam) and then Is_Entity_Name (Name (N)) then Set_Entity (Name (N), Nam); end if; return True; else return False; end if; end Try_Indexed_Call; -------------------------- -- Try_Object_Operation -- -------------------------- function Try_Object_Operation (N : Node_Id; CW_Test_Only : Boolean := False; Allow_Extensions : Boolean := False) return Boolean is K : constant Node_Kind := Nkind (Parent (N)); Is_Subprg_Call : constant Boolean := K in N_Subprogram_Call; Loc : constant Source_Ptr := Sloc (N); Obj : constant Node_Id := Prefix (N); Subprog : constant Node_Id := Make_Identifier (Sloc (Selector_Name (N)), Chars => Chars (Selector_Name (N))); -- Identifier on which possible interpretations will be collected Report_Error : Boolean := False; -- If no candidate interpretation matches the context, redo analysis -- with Report_Error True to provide additional information. Actual : Node_Id; Candidate : Entity_Id := Empty; New_Call_Node : Node_Id := Empty; Node_To_Replace : Node_Id; Obj_Type : Entity_Id := Etype (Obj); Success : Boolean := False; procedure Complete_Object_Operation (Call_Node : Node_Id; Node_To_Replace : Node_Id); -- Make Subprog the name of Call_Node, replace Node_To_Replace with -- Call_Node, insert the object (or its dereference) as the first actual -- in the call, and complete the analysis of the call. procedure Report_Ambiguity (Op : Entity_Id); -- If a prefixed procedure call is ambiguous, indicate whether the call -- includes an implicit dereference or an implicit 'Access. procedure Transform_Object_Operation (Call_Node : out Node_Id; Node_To_Replace : out Node_Id); -- Transform Obj.Operation (X, Y, ...) into Operation (Obj, X, Y ...). -- Call_Node is the resulting subprogram call, Node_To_Replace is -- either N or the parent of N, and Subprog is a reference to the -- subprogram we are trying to match. Note that the transformation -- may be partially destructive for the parent of N, so it needs to -- be undone in the case where Try_Object_Operation returns false. function Try_Class_Wide_Operation (Call_Node : Node_Id; Node_To_Replace : Node_Id) return Boolean; -- Traverse all ancestor types looking for a class-wide subprogram for -- which the current operation is a valid non-dispatching call. procedure Try_One_Prefix_Interpretation (T : Entity_Id); -- If prefix is overloaded, its interpretation may include different -- tagged types, and we must examine the primitive operations and the -- class-wide operations of each in order to find candidate -- interpretations for the call as a whole. function Try_Primitive_Operation (Call_Node : Node_Id; Node_To_Replace : Node_Id) return Boolean; -- Traverse the list of primitive subprograms looking for a dispatching -- operation for which the current node is a valid call. function Valid_Candidate (Success : Boolean; Call : Node_Id; Subp : Entity_Id) return Entity_Id; -- If the subprogram is a valid interpretation, record it, and add to -- the list of interpretations of Subprog. Otherwise return Empty. ------------------------------- -- Complete_Object_Operation -- ------------------------------- procedure Complete_Object_Operation (Call_Node : Node_Id; Node_To_Replace : Node_Id) is Control : constant Entity_Id := First_Formal (Entity (Subprog)); Formal_Type : constant Entity_Id := Etype (Control); First_Actual : Node_Id; begin -- Place the name of the operation, with its interpretations, -- on the rewritten call. Set_Name (Call_Node, Subprog); First_Actual := First (Parameter_Associations (Call_Node)); -- For cross-reference purposes, treat the new node as being in the -- source if the original one is. Set entity and type, even though -- they may be overwritten during resolution if overloaded. Set_Comes_From_Source (Subprog, Comes_From_Source (N)); Set_Comes_From_Source (Call_Node, Comes_From_Source (N)); if Nkind (N) = N_Selected_Component and then not Inside_A_Generic then Set_Entity (Selector_Name (N), Entity (Subprog)); Set_Etype (Selector_Name (N), Etype (Entity (Subprog))); end if; -- If need be, rewrite first actual as an explicit dereference. If -- the call is overloaded, the rewriting can only be done once the -- primitive operation is identified. if Is_Overloaded (Subprog) then -- The prefix itself may be overloaded, and its interpretations -- must be propagated to the new actual in the call. if Is_Overloaded (Obj) then Save_Interps (Obj, First_Actual); end if; Rewrite (First_Actual, Obj); elsif not Is_Access_Type (Formal_Type) and then Is_Access_Type (Etype (Obj)) then Rewrite (First_Actual, Make_Explicit_Dereference (Sloc (Obj), Obj)); Analyze (First_Actual); -- If we need to introduce an explicit dereference, verify that -- the resulting actual is compatible with the mode of the formal. if Ekind (First_Formal (Entity (Subprog))) /= E_In_Parameter and then Is_Access_Constant (Etype (Obj)) then Error_Msg_NE ("expect variable in call to&", Prefix (N), Entity (Subprog)); end if; -- Conversely, if the formal is an access parameter and the object is -- not an access type or a reference type (i.e. a type with the -- Implicit_Dereference aspect specified), replace the actual with a -- 'Access reference. Its analysis will check that the object is -- aliased. elsif Is_Access_Type (Formal_Type) and then not Is_Access_Type (Etype (Obj)) and then (not Has_Implicit_Dereference (Etype (Obj)) or else not Is_Access_Type (Designated_Type (Etype (Get_Reference_Discriminant (Etype (Obj)))))) then -- A special case: A.all'Access is illegal if A is an access to a -- constant and the context requires an access to a variable. if not Is_Access_Constant (Formal_Type) then if (Nkind (Obj) = N_Explicit_Dereference and then Is_Access_Constant (Etype (Prefix (Obj)))) or else not Is_Variable (Obj) then Error_Msg_NE ("actual for & must be a variable", Obj, Control); end if; end if; Rewrite (First_Actual, Make_Attribute_Reference (Loc, Attribute_Name => Name_Access, Prefix => Relocate_Node (Obj))); -- If the object is not overloaded verify that taking access of -- it is legal. Otherwise check is made during resolution. if not Is_Overloaded (Obj) and then not Is_Aliased_View (Obj) then Error_Msg_NE ("object in prefixed call to & must be aliased " & "(RM 4.1.3 (13 1/2))", Prefix (First_Actual), Subprog); end if; Analyze (First_Actual); else if Is_Overloaded (Obj) then Save_Interps (Obj, First_Actual); end if; Rewrite (First_Actual, Obj); end if; if In_Extended_Main_Source_Unit (Current_Scope) then -- The operation is obtained from the dispatch table and not by -- visibility, and may be declared in a unit that is not -- explicitly referenced in the source, but is nevertheless -- required in the context of the current unit. Indicate that -- operation and its scope are referenced, to prevent spurious and -- misleading warnings. If the operation is overloaded, all -- primitives are in the same scope and we can use any of them. -- Don't do that outside the main unit since otherwise this will -- e.g. prevent the detection of some unused with clauses. Set_Referenced (Entity (Subprog), True); Set_Referenced (Scope (Entity (Subprog)), True); end if; Rewrite (Node_To_Replace, Call_Node); -- Propagate the interpretations collected in subprog to the new -- function call node, to be resolved from context. if Is_Overloaded (Subprog) then Save_Interps (Subprog, Node_To_Replace); else Analyze (Node_To_Replace); -- If the operation has been rewritten into a call, which may get -- subsequently an explicit dereference, preserve the type on the -- original node (selected component or indexed component) for -- subsequent legality tests, e.g. Is_Variable. which examines -- the original node. if Nkind (Node_To_Replace) = N_Function_Call then Set_Etype (Original_Node (Node_To_Replace), Etype (Node_To_Replace)); end if; end if; end Complete_Object_Operation; ---------------------- -- Report_Ambiguity -- ---------------------- procedure Report_Ambiguity (Op : Entity_Id) is Access_Actual : constant Boolean := Is_Access_Type (Etype (Prefix (N))); Access_Formal : Boolean := False; begin Error_Msg_Sloc := Sloc (Op); if Present (First_Formal (Op)) then Access_Formal := Is_Access_Type (Etype (First_Formal (Op))); end if; if Access_Formal and then not Access_Actual then if Nkind (Parent (Op)) = N_Full_Type_Declaration then Error_Msg_N ("\possible interpretation " & "(inherited, with implicit 'Access) #", N); else Error_Msg_N ("\possible interpretation (with implicit 'Access) #", N); end if; elsif not Access_Formal and then Access_Actual then if Nkind (Parent (Op)) = N_Full_Type_Declaration then Error_Msg_N ("\possible interpretation " & "(inherited, with implicit dereference) #", N); else Error_Msg_N ("\possible interpretation (with implicit dereference) #", N); end if; else if Nkind (Parent (Op)) = N_Full_Type_Declaration then Error_Msg_N ("\possible interpretation (inherited)#", N); else Error_Msg_N -- CODEFIX ("\possible interpretation#", N); end if; end if; end Report_Ambiguity; -------------------------------- -- Transform_Object_Operation -- -------------------------------- procedure Transform_Object_Operation (Call_Node : out Node_Id; Node_To_Replace : out Node_Id) is Dummy : constant Node_Id := New_Copy (Obj); -- Placeholder used as a first parameter in the call, replaced -- eventually by the proper object. Parent_Node : constant Node_Id := Parent (N); Actual : Node_Id; Actuals : List_Id; begin -- Common case covering 1) Call to a procedure and 2) Call to a -- function that has some additional actuals. if Nkind (Parent_Node) in N_Subprogram_Call -- N is a selected component node containing the name of the -- subprogram. If N is not the name of the parent node we must -- not replace the parent node by the new construct. This case -- occurs when N is a parameterless call to a subprogram that -- is an actual parameter of a call to another subprogram. For -- example: -- Some_Subprogram (..., Obj.Operation, ...) and then N = Name (Parent_Node) then Node_To_Replace := Parent_Node; Actuals := Parameter_Associations (Parent_Node); if Present (Actuals) then Prepend (Dummy, Actuals); else Actuals := New_List (Dummy); end if; if Nkind (Parent_Node) = N_Procedure_Call_Statement then Call_Node := Make_Procedure_Call_Statement (Loc, Name => New_Copy (Subprog), Parameter_Associations => Actuals); else Call_Node := Make_Function_Call (Loc, Name => New_Copy (Subprog), Parameter_Associations => Actuals); end if; -- Before analysis, a function call appears as an indexed component -- if there are no named associations. elsif Nkind (Parent_Node) = N_Indexed_Component and then N = Prefix (Parent_Node) then Node_To_Replace := Parent_Node; Actuals := Expressions (Parent_Node); Actual := First (Actuals); while Present (Actual) loop Analyze (Actual); Next (Actual); end loop; Prepend (Dummy, Actuals); Call_Node := Make_Function_Call (Loc, Name => New_Copy (Subprog), Parameter_Associations => Actuals); -- Parameterless call: Obj.F is rewritten as F (Obj) else Node_To_Replace := N; Call_Node := Make_Function_Call (Loc, Name => New_Copy (Subprog), Parameter_Associations => New_List (Dummy)); end if; end Transform_Object_Operation; ------------------------------ -- Try_Class_Wide_Operation -- ------------------------------ function Try_Class_Wide_Operation (Call_Node : Node_Id; Node_To_Replace : Node_Id) return Boolean is Anc_Type : Entity_Id; Matching_Op : Entity_Id := Empty; Error : Boolean; procedure Traverse_Homonyms (Anc_Type : Entity_Id; Error : out Boolean); -- Traverse the homonym chain of the subprogram searching for those -- homonyms whose first formal has the Anc_Type's class-wide type, -- or an anonymous access type designating the class-wide type. If -- an ambiguity is detected, then Error is set to True. procedure Traverse_Interfaces (Anc_Type : Entity_Id; Error : out Boolean); -- Traverse the list of interfaces, if any, associated with Anc_Type -- and search for acceptable class-wide homonyms associated with each -- interface. If an ambiguity is detected, then Error is set to True. ----------------------- -- Traverse_Homonyms -- ----------------------- procedure Traverse_Homonyms (Anc_Type : Entity_Id; Error : out Boolean) is function First_Formal_Match (Subp_Id : Entity_Id; Typ : Entity_Id) return Boolean; -- Predicate to verify that the first foramal of class-wide -- subprogram Subp_Id matches type Typ of the prefix. ------------------------ -- First_Formal_Match -- ------------------------ function First_Formal_Match (Subp_Id : Entity_Id; Typ : Entity_Id) return Boolean is Ctrl : constant Entity_Id := First_Formal (Subp_Id); begin return Present (Ctrl) and then (Base_Type (Etype (Ctrl)) = Typ or else (Ekind (Etype (Ctrl)) = E_Anonymous_Access_Type and then Base_Type (Designated_Type (Etype (Ctrl))) = Typ)); end First_Formal_Match; -- Local variables CW_Typ : constant Entity_Id := Class_Wide_Type (Anc_Type); Candidate : Entity_Id; -- If homonym is a renaming, examine the renamed program Hom : Entity_Id; Hom_Ref : Node_Id; Success : Boolean; -- Start of processing for Traverse_Homonyms begin Error := False; -- Find a non-hidden operation whose first parameter is of the -- class-wide type, a subtype thereof, or an anonymous access -- to same. If in an instance, the operation can be considered -- even if hidden (it may be hidden because the instantiation -- is expanded after the containing package has been analyzed). -- If the subprogram is a generic actual in an enclosing instance, -- it appears as a renaming that is a candidate interpretation as -- well. Hom := Current_Entity (Subprog); while Present (Hom) loop if Ekind (Hom) in E_Procedure | E_Function and then Present (Renamed_Entity (Hom)) and then Is_Generic_Actual_Subprogram (Hom) and then In_Open_Scopes (Scope (Hom)) then Candidate := Renamed_Entity (Hom); else Candidate := Hom; end if; if Ekind (Candidate) in E_Function | E_Procedure and then (not Is_Hidden (Candidate) or else In_Instance) and then Scope (Candidate) = Scope (Base_Type (Anc_Type)) and then First_Formal_Match (Candidate, CW_Typ) then -- If the context is a procedure call, ignore functions -- in the name of the call. if Ekind (Candidate) = E_Function and then Nkind (Parent (N)) = N_Procedure_Call_Statement and then N = Name (Parent (N)) then goto Next_Hom; -- If the context is a function call, ignore procedures -- in the name of the call. elsif Ekind (Candidate) = E_Procedure and then Nkind (Parent (N)) /= N_Procedure_Call_Statement then goto Next_Hom; end if; Set_Etype (Call_Node, Any_Type); Set_Is_Overloaded (Call_Node, False); Success := False; if No (Matching_Op) then Hom_Ref := New_Occurrence_Of (Candidate, Sloc (Subprog)); Set_Etype (Call_Node, Any_Type); Set_Name (Call_Node, Hom_Ref); Set_Parent (Call_Node, Parent (Node_To_Replace)); Analyze_One_Call (N => Call_Node, Nam => Candidate, Report => Report_Error, Success => Success, Skip_First => True); Matching_Op := Valid_Candidate (Success, Call_Node, Candidate); else Analyze_One_Call (N => Call_Node, Nam => Candidate, Report => Report_Error, Success => Success, Skip_First => True); -- The same operation may be encountered on two homonym -- traversals, before and after looking at interfaces. -- Check for this case before reporting a real ambiguity. if Present (Valid_Candidate (Success, Call_Node, Candidate)) and then Nkind (Call_Node) /= N_Function_Call and then Candidate /= Matching_Op then Error_Msg_NE ("ambiguous call to&", N, Hom); Report_Ambiguity (Matching_Op); Report_Ambiguity (Hom); Check_Ambiguous_Aggregate (New_Call_Node); Error := True; return; end if; end if; end if; <> Hom := Homonym (Hom); end loop; end Traverse_Homonyms; ------------------------- -- Traverse_Interfaces -- ------------------------- procedure Traverse_Interfaces (Anc_Type : Entity_Id; Error : out Boolean) is Intface_List : constant List_Id := Abstract_Interface_List (Anc_Type); Intface : Node_Id; begin Error := False; -- When climbing through the parents of an interface type, -- look for acceptable class-wide homonyms associated with -- the interface type. if Is_Interface (Anc_Type) then Traverse_Homonyms (Anc_Type, Error); if Error then return; end if; end if; Intface := First (Intface_List); while Present (Intface) loop -- Look for acceptable class-wide homonyms associated with the -- interface type. Traverse_Homonyms (Etype (Intface), Error); if Error then return; end if; -- Continue the search by looking at each of the interface's -- associated interface ancestors. Traverse_Interfaces (Etype (Intface), Error); if Error then return; end if; Next (Intface); end loop; -- For derived interface types continue the search climbing to -- the parent type. if Is_Interface (Anc_Type) and then Etype (Anc_Type) /= Anc_Type then Traverse_Interfaces (Etype (Anc_Type), Error); end if; end Traverse_Interfaces; -- Start of processing for Try_Class_Wide_Operation begin -- If we are searching only for conflicting class-wide subprograms -- then initialize directly Matching_Op with the target entity. if CW_Test_Only then Matching_Op := Entity (Selector_Name (N)); end if; -- Loop through ancestor types (including interfaces), traversing -- the homonym chain of the subprogram, trying out those homonyms -- whose first formal has the class-wide type of the ancestor, or -- an anonymous access type designating the class-wide type. Anc_Type := Obj_Type; loop -- Look for a match among homonyms associated with the ancestor Traverse_Homonyms (Anc_Type, Error); if Error then return True; end if; -- Continue the search for matches among homonyms associated with -- any interfaces implemented by the ancestor. Traverse_Interfaces (Anc_Type, Error); if Error then return True; end if; exit when Etype (Anc_Type) = Anc_Type; Anc_Type := Etype (Anc_Type); end loop; if Present (Matching_Op) then Set_Etype (Call_Node, Etype (Matching_Op)); end if; return Present (Matching_Op); end Try_Class_Wide_Operation; ----------------------------------- -- Try_One_Prefix_Interpretation -- ----------------------------------- procedure Try_One_Prefix_Interpretation (T : Entity_Id) is Prev_Obj_Type : constant Entity_Id := Obj_Type; -- If the interpretation does not have a valid candidate type, -- preserve current value of Obj_Type for subsequent errors. begin Obj_Type := T; if Is_Access_Type (Obj_Type) then Obj_Type := Designated_Type (Obj_Type); end if; if Ekind (Obj_Type) in E_Private_Subtype | E_Record_Subtype_With_Private then Obj_Type := Base_Type (Obj_Type); end if; if Is_Class_Wide_Type (Obj_Type) then Obj_Type := Etype (Class_Wide_Type (Obj_Type)); end if; -- The type may have be obtained through a limited_with clause, -- in which case the primitive operations are available on its -- nonlimited view. If still incomplete, retrieve full view. if Ekind (Obj_Type) = E_Incomplete_Type and then From_Limited_With (Obj_Type) and then Has_Non_Limited_View (Obj_Type) then Obj_Type := Get_Full_View (Non_Limited_View (Obj_Type)); end if; -- If the object is not tagged, or the type is still an incomplete -- type, this is not a prefixed call. Restore the previous type as -- the current one is not a legal candidate. -- Extension feature: Calls with prefixed views are also supported -- for untagged types, so skip the early return when extensions are -- enabled, unless the type doesn't have a primitive operations list -- (such as in the case of predefined types). if (not Is_Tagged_Type (Obj_Type) and then (not (Core_Extensions_Allowed or Allow_Extensions) or else No (Primitive_Operations (Obj_Type)))) or else Is_Incomplete_Type (Obj_Type) then Obj_Type := Prev_Obj_Type; return; end if; declare Dup_Call_Node : constant Node_Id := New_Copy (New_Call_Node); Ignore : Boolean; Prim_Result : Boolean := False; begin if not CW_Test_Only then Prim_Result := Try_Primitive_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace); -- Extension feature: In the case where the prefix is of an -- access type, and a primitive wasn't found for the designated -- type, then if the access type has primitives we attempt a -- prefixed call using one of its primitives. (It seems that -- this isn't quite right to give preference to the designated -- type in the case where both the access and designated types -- have homographic prefixed-view operations that could result -- in an ambiguity, but handling properly may be tricky. ???) if (Core_Extensions_Allowed or Allow_Extensions) and then not Prim_Result and then Is_Named_Access_Type (Prev_Obj_Type) and then Present (Direct_Primitive_Operations (Prev_Obj_Type)) then -- Temporarily reset Obj_Type to the original access type Obj_Type := Prev_Obj_Type; Prim_Result := Try_Primitive_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace); -- Restore Obj_Type to the designated type (is this really -- necessary, or should it only be done when Prim_Result is -- still False?). Obj_Type := Designated_Type (Obj_Type); end if; end if; -- Check if there is a class-wide subprogram covering the -- primitive. This check must be done even if a candidate -- was found in order to report ambiguous calls. if not Prim_Result then Ignore := Try_Class_Wide_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace); -- If we found a primitive we search for class-wide subprograms -- using a duplicate of the call node (done to avoid missing its -- decoration if there is no ambiguity). else Ignore := Try_Class_Wide_Operation (Call_Node => Dup_Call_Node, Node_To_Replace => Node_To_Replace); end if; end; end Try_One_Prefix_Interpretation; ----------------------------- -- Try_Primitive_Operation -- ----------------------------- function Try_Primitive_Operation (Call_Node : Node_Id; Node_To_Replace : Node_Id) return Boolean is Elmt : Elmt_Id; Prim_Op : Entity_Id; Matching_Op : Entity_Id := Empty; Prim_Op_Ref : Node_Id := Empty; Corr_Type : Entity_Id := Empty; -- If the prefix is a synchronized type, the controlling type of -- the primitive operation is the corresponding record type, else -- this is the object type itself. Success : Boolean := False; function Collect_Generic_Type_Ops (T : Entity_Id) return Elist_Id; -- For tagged types the candidate interpretations are found in -- the list of primitive operations of the type and its ancestors. -- For formal tagged types we have to find the operations declared -- in the same scope as the type (including in the generic formal -- part) because the type itself carries no primitive operations, -- except for formal derived types that inherit the operations of -- the parent and progenitors. -- -- If the context is a generic subprogram body, the generic formals -- are visible by name, but are not in the entity list of the -- subprogram because that list starts with the subprogram formals. -- We retrieve the candidate operations from the generic declaration. function Extended_Primitive_Ops (T : Entity_Id) return Elist_Id; -- Prefix notation can also be used on operations that are not -- primitives of the type, but are declared in the same immediate -- declarative part, which can only mean the corresponding package -- body (see RM 4.1.3 (9.2/3)). If we are in that body we extend the -- list of primitives with body operations with the same name that -- may be candidates, so that Try_Primitive_Operations can examine -- them if no real primitive is found. function Is_Private_Overriding (Op : Entity_Id) return Boolean; -- An operation that overrides an inherited operation in the private -- part of its package may be hidden, but if the inherited operation -- is visible a direct call to it will dispatch to the private one, -- which is therefore a valid candidate. function Names_Match (Obj_Type : Entity_Id; Prim_Op : Entity_Id; Subprog : Entity_Id) return Boolean; -- Return True if the names of Prim_Op and Subprog match. If Obj_Type -- is a protected type then compare also the original name of Prim_Op -- with the name of Subprog (since the expander may have added a -- prefix to its original name --see Exp_Ch9.Build_Selected_Name). function Valid_First_Argument_Of (Op : Entity_Id) return Boolean; -- Verify that the prefix, dereferenced if need be, is a valid -- controlling argument in a call to Op. The remaining actuals -- are checked in the subsequent call to Analyze_One_Call. ------------------------------ -- Collect_Generic_Type_Ops -- ------------------------------ function Collect_Generic_Type_Ops (T : Entity_Id) return Elist_Id is Bas : constant Entity_Id := Base_Type (T); Candidates : constant Elist_Id := New_Elmt_List; Subp : Entity_Id; Formal : Entity_Id; procedure Check_Candidate; -- The operation is a candidate if its first parameter is a -- controlling operand of the desired type. ----------------------- -- Check_Candidate; -- ----------------------- procedure Check_Candidate is begin Formal := First_Formal (Subp); if Present (Formal) and then Is_Controlling_Formal (Formal) and then (Base_Type (Etype (Formal)) = Bas or else (Is_Access_Type (Etype (Formal)) and then Designated_Type (Etype (Formal)) = Bas)) then Append_Elmt (Subp, Candidates); end if; end Check_Candidate; -- Start of processing for Collect_Generic_Type_Ops begin if Is_Derived_Type (T) then return Primitive_Operations (T); elsif Ekind (Scope (T)) in E_Procedure | E_Function then -- Scan the list of generic formals to find subprograms -- that may have a first controlling formal of the type. if Nkind (Unit_Declaration_Node (Scope (T))) = N_Generic_Subprogram_Declaration then declare Decl : Node_Id; begin Decl := First (Generic_Formal_Declarations (Unit_Declaration_Node (Scope (T)))); while Present (Decl) loop if Nkind (Decl) in N_Formal_Subprogram_Declaration then Subp := Defining_Entity (Decl); Check_Candidate; end if; Next (Decl); end loop; end; end if; return Candidates; else -- Scan the list of entities declared in the same scope as -- the type. In general this will be an open scope, given that -- the call we are analyzing can only appear within a generic -- declaration or body (either the one that declares T, or a -- child unit). -- For a subtype representing a generic actual type, go to the -- base type. if Is_Generic_Actual_Type (T) then Subp := First_Entity (Scope (Base_Type (T))); else Subp := First_Entity (Scope (T)); end if; while Present (Subp) loop if Is_Overloadable (Subp) then Check_Candidate; end if; Next_Entity (Subp); end loop; return Candidates; end if; end Collect_Generic_Type_Ops; ---------------------------- -- Extended_Primitive_Ops -- ---------------------------- function Extended_Primitive_Ops (T : Entity_Id) return Elist_Id is Type_Scope : constant Entity_Id := Scope (T); Op_List : Elist_Id := Primitive_Operations (T); begin if Is_Package_Or_Generic_Package (Type_Scope) and then ((In_Package_Body (Type_Scope) and then In_Open_Scopes (Type_Scope)) or else In_Instance_Body) then -- Retrieve list of declarations of package body if possible declare The_Body : constant Node_Id := Corresponding_Body (Unit_Declaration_Node (Type_Scope)); begin if Present (The_Body) then declare Body_Decls : constant List_Id := Declarations (Unit_Declaration_Node (The_Body)); Op_Found : Boolean := False; Op : Entity_Id := Current_Entity (Subprog); begin while Present (Op) loop if Comes_From_Source (Op) and then Is_Overloadable (Op) -- Exclude overriding primitive operations of a -- type extension declared in the package body, -- to prevent duplicates in extended list. and then not Is_Primitive (Op) and then Is_List_Member (Unit_Declaration_Node (Op)) and then List_Containing (Unit_Declaration_Node (Op)) = Body_Decls then if not Op_Found then -- Copy list of primitives so it is not -- affected for other uses. Op_List := New_Copy_Elist (Op_List); Op_Found := True; end if; Append_Elmt (Op, Op_List); end if; Op := Homonym (Op); end loop; end; end if; end; end if; return Op_List; end Extended_Primitive_Ops; --------------------------- -- Is_Private_Overriding -- --------------------------- function Is_Private_Overriding (Op : Entity_Id) return Boolean is Visible_Op : Entity_Id; begin -- The subprogram may be overloaded with both visible and private -- entities with the same name. We have to scan the chain of -- homonyms to determine whether there is a previous implicit -- declaration in the same scope that is overridden by the -- private candidate. Visible_Op := Homonym (Op); while Present (Visible_Op) loop if Scope (Op) /= Scope (Visible_Op) then return False; elsif not Comes_From_Source (Visible_Op) and then Alias (Visible_Op) = Op then -- If Visible_Op or what it overrides is not hidden, then we -- have found what we're looking for. if not Is_Hidden (Visible_Op) or else not Is_Hidden (Overridden_Operation (Op)) then return True; end if; end if; Visible_Op := Homonym (Visible_Op); end loop; return False; end Is_Private_Overriding; ----------------- -- Names_Match -- ----------------- function Names_Match (Obj_Type : Entity_Id; Prim_Op : Entity_Id; Subprog : Entity_Id) return Boolean is begin -- Common case: exact match if Chars (Prim_Op) = Chars (Subprog) then return True; -- For protected type primitives the expander may have built the -- name of the dispatching primitive prepending the type name to -- avoid conflicts with the name of the protected subprogram (see -- Exp_Ch9.Build_Selected_Name). elsif Is_Protected_Type (Obj_Type) then return Present (Original_Protected_Subprogram (Prim_Op)) and then Chars (Original_Protected_Subprogram (Prim_Op)) = Chars (Subprog); -- In an instance, the selector name may be a generic actual that -- renames a primitive operation of the type of the prefix. elsif In_Instance and then Present (Current_Entity (Subprog)) then declare Subp : constant Entity_Id := Current_Entity (Subprog); begin if Present (Subp) and then Is_Subprogram (Subp) and then Present (Renamed_Entity (Subp)) and then Is_Generic_Actual_Subprogram (Subp) and then Chars (Renamed_Entity (Subp)) = Chars (Prim_Op) then return True; end if; end; end if; return False; end Names_Match; ----------------------------- -- Valid_First_Argument_Of -- ----------------------------- function Valid_First_Argument_Of (Op : Entity_Id) return Boolean is Typ : Entity_Id := Etype (First_Formal (Op)); begin if Is_Concurrent_Type (Typ) and then Present (Corresponding_Record_Type (Typ)) then Typ := Corresponding_Record_Type (Typ); end if; -- Simple case. Object may be a subtype of the tagged type or may -- be the corresponding record of a synchronized type. return Obj_Type = Typ or else Base_Type (Obj_Type) = Base_Type (Typ) or else Corr_Type = Typ -- Object may be of a derived type whose parent has unknown -- discriminants, in which case the type matches the underlying -- record view of its base. or else (Has_Unknown_Discriminants (Typ) and then Typ = Underlying_Record_View (Base_Type (Obj_Type))) -- Prefix can be dereferenced or else (Is_Access_Type (Corr_Type) and then Designated_Type (Corr_Type) = Typ) -- Formal is an access parameter, for which the object can -- provide an access. or else (Ekind (Typ) = E_Anonymous_Access_Type and then Base_Type (Designated_Type (Typ)) = Base_Type (Corr_Type)); end Valid_First_Argument_Of; -- Start of processing for Try_Primitive_Operation begin -- Look for subprograms in the list of primitive operations. The name -- must be identical, and the kind of call indicates the expected -- kind of operation (function or procedure). If the type is a -- (tagged) synchronized type, the primitive ops are attached to the -- corresponding record (base) type. if Is_Concurrent_Type (Obj_Type) then if Present (Corresponding_Record_Type (Obj_Type)) then Corr_Type := Base_Type (Corresponding_Record_Type (Obj_Type)); Elmt := First_Elmt (Primitive_Operations (Corr_Type)); else Corr_Type := Obj_Type; Elmt := First_Elmt (Collect_Generic_Type_Ops (Obj_Type)); end if; elsif not Is_Generic_Type (Obj_Type) then Corr_Type := Obj_Type; Elmt := First_Elmt (Extended_Primitive_Ops (Obj_Type)); else Corr_Type := Obj_Type; Elmt := First_Elmt (Collect_Generic_Type_Ops (Obj_Type)); end if; while Present (Elmt) loop Prim_Op := Node (Elmt); if Names_Match (Obj_Type, Prim_Op, Subprog) and then Present (First_Formal (Prim_Op)) and then Valid_First_Argument_Of (Prim_Op) and then (Nkind (Call_Node) = N_Function_Call) = (Ekind (Prim_Op) = E_Function) then -- Ada 2005 (AI-251): If this primitive operation corresponds -- to an immediate ancestor interface there is no need to add -- it to the list of interpretations; the corresponding aliased -- primitive is also in this list of primitive operations and -- will be used instead. if (Present (Interface_Alias (Prim_Op)) and then Is_Ancestor (Find_Dispatching_Type (Alias (Prim_Op)), Corr_Type)) -- Do not consider hidden primitives unless the type is in an -- open scope or we are within an instance, where visibility -- is known to be correct, or else if this is an overriding -- operation in the private part for an inherited operation. or else (Is_Hidden (Prim_Op) and then not Is_Immediately_Visible (Obj_Type) and then not In_Instance and then not Is_Private_Overriding (Prim_Op)) then goto Continue; end if; Set_Etype (Call_Node, Any_Type); Set_Is_Overloaded (Call_Node, False); if No (Matching_Op) then Prim_Op_Ref := New_Occurrence_Of (Prim_Op, Sloc (Subprog)); Candidate := Prim_Op; Set_Parent (Call_Node, Parent (Node_To_Replace)); Set_Name (Call_Node, Prim_Op_Ref); Success := False; Analyze_One_Call (N => Call_Node, Nam => Prim_Op, Report => Report_Error, Success => Success, Skip_First => True); Matching_Op := Valid_Candidate (Success, Call_Node, Prim_Op); -- More than one interpretation, collect for subsequent -- disambiguation. If this is a procedure call and there -- is another match, report ambiguity now. else Analyze_One_Call (N => Call_Node, Nam => Prim_Op, Report => Report_Error, Success => Success, Skip_First => True); if Present (Valid_Candidate (Success, Call_Node, Prim_Op)) and then Nkind (Call_Node) /= N_Function_Call then Error_Msg_NE ("ambiguous call to&", N, Prim_Op); Report_Ambiguity (Matching_Op); Report_Ambiguity (Prim_Op); Check_Ambiguous_Aggregate (Call_Node); return True; end if; end if; end if; <> Next_Elmt (Elmt); end loop; if Present (Matching_Op) then Set_Etype (Call_Node, Etype (Matching_Op)); end if; return Present (Matching_Op); end Try_Primitive_Operation; --------------------- -- Valid_Candidate -- --------------------- function Valid_Candidate (Success : Boolean; Call : Node_Id; Subp : Entity_Id) return Entity_Id is Arr_Type : Entity_Id; Comp_Type : Entity_Id; begin -- If the subprogram is a valid interpretation, record it in global -- variable Subprog, to collect all possible overloadings. if Success then if Subp /= Entity (Subprog) then Add_One_Interp (Subprog, Subp, Etype (Subp)); end if; end if; -- If the call may be an indexed call, retrieve component type of -- resulting expression, and add possible interpretation. Arr_Type := Empty; Comp_Type := Empty; if Nkind (Call) = N_Function_Call and then Nkind (Parent (N)) = N_Indexed_Component and then Needs_One_Actual (Subp) then if Is_Array_Type (Etype (Subp)) then Arr_Type := Etype (Subp); elsif Is_Access_Type (Etype (Subp)) and then Is_Array_Type (Designated_Type (Etype (Subp))) then Arr_Type := Designated_Type (Etype (Subp)); end if; end if; if Present (Arr_Type) then -- Verify that the actuals (excluding the object) match the types -- of the indexes. declare Actual : Node_Id; Index : Node_Id; begin Actual := Next (First_Actual (Call)); Index := First_Index (Arr_Type); while Present (Actual) and then Present (Index) loop if not Has_Compatible_Type (Actual, Etype (Index)) then Arr_Type := Empty; exit; end if; Next_Actual (Actual); Next_Index (Index); end loop; if No (Actual) and then No (Index) and then Present (Arr_Type) then Comp_Type := Component_Type (Arr_Type); end if; end; if Present (Comp_Type) and then Etype (Subprog) /= Comp_Type then Add_One_Interp (Subprog, Subp, Comp_Type); end if; end if; if Etype (Call) /= Any_Type then return Subp; else return Empty; end if; end Valid_Candidate; -- Start of processing for Try_Object_Operation begin Analyze_Expression (Obj); -- Analyze the actuals if node is known to be a subprogram call if Is_Subprg_Call and then N = Name (Parent (N)) then Actual := First (Parameter_Associations (Parent (N))); while Present (Actual) loop Analyze_Expression (Actual); Next (Actual); end loop; end if; -- Build a subprogram call node, using a copy of Obj as its first -- actual. This is a placeholder, to be replaced by an explicit -- dereference when needed. Transform_Object_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace); Set_Etype (New_Call_Node, Any_Type); Set_Etype (Subprog, Any_Type); Set_Parent (New_Call_Node, Parent (Node_To_Replace)); if not Is_Overloaded (Obj) then Try_One_Prefix_Interpretation (Obj_Type); else declare I : Interp_Index; It : Interp; begin Get_First_Interp (Obj, I, It); while Present (It.Nam) loop Try_One_Prefix_Interpretation (It.Typ); Get_Next_Interp (I, It); end loop; end; end if; if Etype (New_Call_Node) /= Any_Type then -- No need to complete the tree transformations if we are only -- searching for conflicting class-wide subprograms if CW_Test_Only then return False; else Complete_Object_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace); return True; end if; elsif Present (Candidate) then -- The argument list is not type correct. Re-analyze with error -- reporting enabled, and use one of the possible candidates. -- In All_Errors_Mode, re-analyze all failed interpretations. if All_Errors_Mode then Report_Error := True; if Try_Primitive_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace) or else Try_Class_Wide_Operation (Call_Node => New_Call_Node, Node_To_Replace => Node_To_Replace) then null; end if; else Analyze_One_Call (N => New_Call_Node, Nam => Candidate, Report => True, Success => Success, Skip_First => True); -- The error may hot have been reported yet for overloaded -- prefixed calls, depending on the non-matching candidate, -- in which case provide a concise error now. if Serious_Errors_Detected = 0 then Error_Msg_NE ("cannot resolve prefixed call to primitive operation of&", N, Entity (Obj)); end if; end if; -- No need for further errors return True; else -- There was no candidate operation, but Analyze_Selected_Component -- may continue the analysis so we need to undo the change possibly -- made to the Parent of N earlier by Transform_Object_Operation. declare Parent_Node : constant Node_Id := Parent (N); begin if Node_To_Replace = Parent_Node then Remove (First (Parameter_Associations (New_Call_Node))); Set_Parent (Parameter_Associations (New_Call_Node), Parent_Node); end if; end; return False; end if; end Try_Object_Operation; ------------------------- -- Unresolved_Operator -- ------------------------- procedure Unresolved_Operator (N : Node_Id) is L : constant Node_Id := (if Nkind (N) in N_Binary_Op then Left_Opnd (N) else Empty); R : constant Node_Id := Right_Opnd (N); Op_Id : Entity_Id; begin -- Note that in the following messages, if the operand is overloaded we -- choose an arbitrary type to complain about, but that is probably more -- useful than not giving a type at all. if Nkind (N) in N_Unary_Op then Error_Msg_Node_2 := Etype (R); Error_Msg_N ("operator& not defined for}", N); elsif Nkind (N) in N_Binary_Op then if not Is_Overloaded (L) and then not Is_Overloaded (R) and then Base_Type (Etype (L)) = Base_Type (Etype (R)) then Error_Msg_Node_2 := First_Subtype (Etype (R)); Error_Msg_N ("there is no applicable operator& for}", N); else -- Another attempt to find a fix: one of the candidate -- interpretations may not be use-visible. This has -- already been checked for predefined operators, so -- we examine only user-defined functions. Op_Id := Get_Name_Entity_Id (Chars (N)); while Present (Op_Id) loop if Ekind (Op_Id) /= E_Operator and then Is_Overloadable (Op_Id) and then not Is_Immediately_Visible (Op_Id) and then not In_Use (Scope (Op_Id)) and then not Is_Abstract_Subprogram (Op_Id) and then not Is_Hidden (Op_Id) and then Ekind (Scope (Op_Id)) = E_Package and then Has_Compatible_Type (L, Etype (First_Formal (Op_Id))) and then Present (Next_Formal (First_Formal (Op_Id))) and then Has_Compatible_Type (R, Etype (Next_Formal (First_Formal (Op_Id)))) then Error_Msg_N ("no legal interpretation for operator&", N); Error_Msg_NE ("\use clause on& would make operation legal", N, Scope (Op_Id)); exit; end if; Op_Id := Homonym (Op_Id); end loop; if No (Op_Id) then if Debug_Flag_Underscore_DD then if Nkind (N) /= N_Op_Concat then if Nkind (N) in N_Op_Multiply | N_Op_Divide and then Is_Fixed_Point_Type (Etype (L)) and then Is_Integer_Type (Etype (R)) then Record_Invalid_Operand_Types_For_Operator_R_Int_Error (Op => N, L => L, L_Type => Etype (L), R => R, R_Type => Etype (R)); elsif Nkind (N) = N_Op_Multiply and then Is_Fixed_Point_Type (Etype (R)) and then Is_Integer_Type (Etype (L)) then Record_Invalid_Operand_Types_For_Operator_L_Int_Error (Op => N, L => L, L_Type => Etype (L), R => R, R_Type => Etype (R)); else Record_Invalid_Operand_Types_For_Operator_Error (Op => N, L => L, L_Type => Etype (L), R => R, R_Type => Etype (R)); end if; elsif Is_Access_Type (Etype (L)) then Record_Invalid_Operand_Types_For_Operator_L_Acc_Error (Op => N, L => L); elsif Is_Access_Type (Etype (R)) then Record_Invalid_Operand_Types_For_Operator_R_Acc_Error (Op => N, R => R); else Record_Invalid_Operand_Types_For_Operator_General_Error (N); end if; else Error_Msg_N ("invalid operand types for operator&", N); if Nkind (N) /= N_Op_Concat then Error_Msg_NE ("\left operand has}!", N, Etype (L)); Error_Msg_NE ("\right operand has}!", N, Etype (R)); -- For multiplication and division operators with -- a fixed-point operand and an integer operand, -- indicate that the integer operand should be of -- type Integer. if Nkind (N) in N_Op_Multiply | N_Op_Divide and then Is_Fixed_Point_Type (Etype (L)) and then Is_Integer_Type (Etype (R)) then Error_Msg_N ("\convert right operand to `Integer`", N); elsif Nkind (N) = N_Op_Multiply and then Is_Fixed_Point_Type (Etype (R)) and then Is_Integer_Type (Etype (L)) then Error_Msg_N ("\convert left operand to `Integer`", N); end if; -- For concatenation operators it is more difficult to -- determine which is the wrong operand. It is worth -- flagging explicitly an access type, for those who -- might think that a dereference happens here. elsif Is_Access_Type (Etype (L)) then Error_Msg_N ("\left operand is access type", N); elsif Is_Access_Type (Etype (R)) then Error_Msg_N ("\right operand is access type", N); end if; end if; end if; end if; end if; end Unresolved_Operator; --------- -- wpo -- --------- procedure wpo (T : Entity_Id) is Op : Entity_Id; E : Elmt_Id; begin if not Is_Tagged_Type (T) then return; end if; E := First_Elmt (Primitive_Operations (Base_Type (T))); while Present (E) loop Op := Node (E); Write_Int (Int (Op)); Write_Str (" === "); Write_Name (Chars (Op)); Write_Str (" in "); Write_Name (Chars (Scope (Op))); Next_Elmt (E); Write_Eol; end loop; end wpo; end Sem_Ch4;