sem_ch5.adb: remove spurious warning from non-empty loop.

2013-04-11  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch5.adb: remove spurious warning from non-empty loop.
	* sem_ch8.adb (Enclosing_Instance): Make public to other routines
	in the package, in order to suppress redundant semantic checks
	on subprogram renamings in nested instantiations.

From-SVN: r197746

3 files changed, 228 insertions, 294 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index d72ad62..a9c5133 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,10 @@
+2013-04-11  Ed Schonberg  <schonberg@adacore.com>
+
+	* sem_ch5.adb: remove spurious warning from non-empty loop.
+	* sem_ch8.adb (Enclosing_Instance): Make public to other routines
+	in the package, in order to suppress redundant semantic checks
+	on subprogram renamings in nested instantiations.
+
 2013-04-11  Robert Dewar  <dewar@adacore.com>
 
 	* errout.ads: Minor reformatting.
diff --git a/gcc/ada/sem_ch5.adb b/gcc/ada/sem_ch5.adb
index 2e8f3a7..d098609 100644
--- a/gcc/ada/sem_ch5.adb
+++ b/gcc/ada/sem_ch5.adb
@@ -141,13 +141,13 @@ package body Sem_Ch5 is
                --  directly.
 
                elsif (Is_Prival (Ent)
-                        and then
-                          (Ekind (Current_Scope) = E_Function
-                             or else Ekind (Enclosing_Dynamic_Scope
-                                             (Current_Scope)) = E_Function))
+                       and then
+                         (Ekind (Current_Scope) = E_Function
+                           or else Ekind (Enclosing_Dynamic_Scope
+                                            (Current_Scope)) = E_Function))
                    or else
                      (Ekind (Ent) = E_Component
-                        and then Is_Protected_Type (Scope (Ent)))
+                       and then Is_Protected_Type (Scope (Ent)))
                then
                   Error_Msg_N
                     ("protected function cannot modify protected object", N);
@@ -222,16 +222,15 @@ package body Sem_Ch5 is
 
          if Is_Entity_Name (Opnd)
            and then (Ekind (Entity (Opnd)) = E_Out_Parameter
-                      or else Ekind (Entity (Opnd)) =
-                           E_In_Out_Parameter
-                      or else Ekind (Entity (Opnd)) =
-                           E_Generic_In_Out_Parameter
+                      or else Ekind_In (Entity (Opnd),
+                                        E_In_Out_Parameter,
+                                        E_Generic_In_Out_Parameter)
                       or else
                         (Ekind (Entity (Opnd)) = E_Variable
                           and then Nkind (Parent (Entity (Opnd))) =
-                             N_Object_Renaming_Declaration
+                                            N_Object_Renaming_Declaration
                           and then Nkind (Parent (Parent (Entity (Opnd)))) =
-                             N_Accept_Statement))
+                                            N_Accept_Statement))
          then
             Opnd_Type := Get_Actual_Subtype (Opnd);
 
@@ -394,7 +393,7 @@ package body Sem_Ch5 is
                end loop;
 
                if (Nkind (Ent) = N_Attribute_Reference
-                     and then Attribute_Name (Ent) = Name_Priority)
+                    and then Attribute_Name (Ent) = Name_Priority)
 
                   --  Renamings of the attribute Priority applied to protected
                   --  objects have been previously expanded into calls to the
@@ -402,15 +401,15 @@ package body Sem_Ch5 is
 
                  or else
                   (Nkind (Ent) = N_Function_Call
-                     and then (Entity (Name (Ent)) = RTE (RE_Get_Ceiling)
-                                or else
-                               Entity (Name (Ent)) = RTE (RO_PE_Get_Ceiling)))
+                    and then (Entity (Name (Ent)) = RTE (RE_Get_Ceiling)
+                               or else
+                              Entity (Name (Ent)) = RTE (RO_PE_Get_Ceiling)))
                then
                   --  The enclosing subprogram cannot be a protected function
 
                   S := Current_Scope;
                   while not (Is_Subprogram (S)
-                               and then Convention (S) = Convention_Protected)
+                              and then Convention (S) = Convention_Protected)
                      and then S /= Standard_Standard
                   loop
                      S := Scope (S);
@@ -583,8 +582,8 @@ package body Sem_Ch5 is
             Propagate_Tag (Lhs, Rhs);
 
          elsif Nkind (Rhs) = N_Function_Call
-              and then Is_Entity_Name (Name (Rhs))
-              and then Is_Abstract_Subprogram (Entity (Name (Rhs)))
+           and then Is_Entity_Name (Name (Rhs))
+           and then Is_Abstract_Subprogram (Entity (Name (Rhs)))
          then
             Error_Msg_N
               ("call to abstract function must be dispatching", Name (Rhs));
@@ -607,9 +606,7 @@ package body Sem_Ch5 is
       --  as well to anonymous access-to-subprogram types that are component
       --  subtypes or formal parameters.
 
-      if Ada_Version >= Ada_2005
-        and then Is_Access_Type (T1)
-      then
+      if Ada_Version >= Ada_2005 and then Is_Access_Type (T1) then
          if Is_Local_Anonymous_Access (T1)
            or else Ekind (T2) = E_Anonymous_Access_Subprogram_Type
 
@@ -665,12 +662,10 @@ package body Sem_Ch5 is
       --  assignment within the block.
 
       elsif Is_Array_Type (T1)
-        and then
-          (Nkind (Rhs) /= N_Type_Conversion
-            or else Is_Constrained (Etype (Rhs)))
-        and then
-          (Nkind (Rhs) /= N_Function_Call
-            or else Nkind (N) /= N_Block_Statement)
+        and then (Nkind (Rhs) /= N_Type_Conversion
+                   or else Is_Constrained (Etype (Rhs)))
+        and then (Nkind (Rhs) /= N_Function_Call
+                   or else Nkind (N) /= N_Block_Statement)
       then
          --  Assignment verifies that the length of the Lsh and Rhs are equal,
          --  but of course the indexes do not have to match. If the right-hand
@@ -1172,7 +1167,7 @@ package body Sem_Ch5 is
 
       elsif Ada_Version = Ada_83
         and then (Is_Generic_Type (Exp_Btype)
-                    or else Is_Generic_Type (Root_Type (Exp_Btype)))
+                   or else Is_Generic_Type (Root_Type (Exp_Btype)))
       then
          Error_Msg_N
            ("(Ada 83) case expression cannot be of a generic type", Exp);
@@ -1198,9 +1193,7 @@ package body Sem_Ch5 is
       --  A case statement with a single OTHERS alternative is not allowed
       --  in SPARK.
 
-      if Others_Present
-        and then List_Length (Alternatives (N)) = 1
-      then
+      if Others_Present and then List_Length (Alternatives (N)) = 1 then
          Check_SPARK_Restriction
            ("OTHERS as unique case alternative is not allowed", N);
       end if;
@@ -1297,9 +1290,7 @@ package body Sem_Ch5 is
          Scope_Id := Scope_Stack.Table (J).Entity;
          Kind := Ekind (Scope_Id);
 
-         if Kind = E_Loop
-           and then (No (Target) or else Scope_Id = U_Name)
-         then
+         if Kind = E_Loop and then (No (Target) or else Scope_Id = U_Name) then
             Set_Has_Exit (Scope_Id);
             exit;
 
@@ -1423,9 +1414,7 @@ package body Sem_Ch5 is
          Scope_Id := Scope_Stack.Table (J).Entity;
 
          if Label_Scope = Scope_Id
-           or else (Ekind (Scope_Id) /= E_Block
-                     and then Ekind (Scope_Id) /= E_Loop
-                     and then Ekind (Scope_Id) /= E_Return_Statement)
+           or else not Ekind_In (Scope_Id, E_Block, E_Loop, E_Return_Statement)
          then
             if Scope_Id /= Label_Scope then
                Error_Msg_N
@@ -1447,9 +1436,9 @@ package body Sem_Ch5 is
 
    --  The expander has circuitry to completely delete code that it can tell
    --  will not be executed (as a result of compile time known conditions). In
-   --  the analyzer, we ensure that code that will be deleted in this manner is
-   --  analyzed but not expanded. This is obviously more efficient, but more
-   --  significantly, difficulties arise if code is expanded and then
+   --  the analyzer, we ensure that code that will be deleted in this manner
+   --  is analyzed but not expanded. This is obviously more efficient, but
+   --  more significantly, difficulties arise if code is expanded and then
    --  eliminated (e.g. exception table entries disappear). Similarly, itypes
    --  generated in deleted code must be frozen from start, because the nodes
    --  on which they depend will not be available at the freeze point.
@@ -2161,15 +2150,11 @@ package body Sem_Ch5 is
          --  Propagate staticness to loop range itself, in case the
          --  corresponding subtype is static.
 
-         if New_Lo /= Lo
-           and then Is_Static_Expression (New_Lo)
-         then
+         if New_Lo /= Lo and then Is_Static_Expression (New_Lo) then
             Rewrite (Low_Bound (R), New_Copy (New_Lo));
          end if;
 
-         if New_Hi /= Hi
-           and then Is_Static_Expression (New_Hi)
-         then
+         if New_Hi /= Hi and then Is_Static_Expression (New_Hi) then
             Rewrite (High_Bound (R), New_Copy (New_Hi));
          end if;
       end Process_Bounds;
@@ -2238,9 +2223,8 @@ package body Sem_Ch5 is
          --  new iterator form.
 
          if Nkind (DS_Copy) = N_Function_Call
-           or else
-             (Is_Entity_Name (DS_Copy)
-               and then not Is_Type (Entity (DS_Copy)))
+           or else (Is_Entity_Name (DS_Copy)
+                     and then not Is_Type (Entity (DS_Copy)))
          then
             --  This is an iterator specification. Rewrite it as such and
             --  analyze it to capture function calls that may require
@@ -2351,7 +2335,7 @@ package body Sem_Ch5 is
              and then Is_Itype (Etype (Id))
              and then Nkind (Parent (Loop_Nod)) = N_Expression_With_Actions
              and then Nkind (Original_Node (Parent (Loop_Nod))) =
-                        N_Quantified_Expression)
+                                                   N_Quantified_Expression)
       then
          Set_Etype (Id, Etype (DS));
       end if;
@@ -2395,9 +2379,8 @@ package body Sem_Ch5 is
                --  instance, since in practice they tend to be dubious in these
                --  cases since they can result from intended parametrization.
 
-               if not Inside_A_Generic
-                 and then not In_Instance
-               then
+               if not Inside_A_Generic and then not In_Instance then
+
                   --  Specialize msg if invalid values could make the loop
                   --  non-null after all.
 
@@ -2436,7 +2419,7 @@ package body Sem_Ch5 is
 
                --  The other case for a warning is a reverse loop where the
                --  upper bound is the integer literal zero or one, and the
-               --  lower bound can be positive.
+               --  lower bound may exceed this value.
 
                --  For example, we have
 
@@ -2449,10 +2432,23 @@ package body Sem_Ch5 is
               and then Nkind (Original_Node (H)) = N_Integer_Literal
               and then
                 (Intval (Original_Node (H)) = Uint_0
-                  or else Intval (Original_Node (H)) = Uint_1)
+                  or else
+                 Intval (Original_Node (H)) = Uint_1)
             then
-               Error_Msg_N ("??loop range may be null", DS);
-               Error_Msg_N ("\??bounds may be wrong way round", DS);
+               --  Lower bound may in fact be known and known not to exceed
+               --  upper bound (e.g. reverse 0 .. 1) and that's OK.
+
+               if Compile_Time_Known_Value (L)
+                 and then Expr_Value (L) <= Expr_Value (H)
+               then
+                  null;
+
+               --  Otherwise warning is warranted
+
+               else
+                  Error_Msg_N ("??loop range may be null", DS);
+                  Error_Msg_N ("\??bounds may be wrong way round", DS);
+               end if;
             end if;
          end;
       end if;
@@ -2839,9 +2835,7 @@ package body Sem_Ch5 is
       P          : Node_Id;
 
    begin
-      if Is_List_Member (N)
-        and then Comes_From_Source (N)
-      then
+      if Is_List_Member (N) and then Comes_From_Source (N) then
          declare
             Nxt : Node_Id;
 
@@ -2993,9 +2987,8 @@ package body Sem_Ch5 is
 
       Analyze (R_Copy);
 
-      if Nkind (R_Copy) in N_Subexpr
-        and then Is_Overloaded (R_Copy)
-      then
+      if Nkind (R_Copy) in N_Subexpr and then Is_Overloaded (R_Copy) then
+
          --  Apply preference rules for range of predefined integer types, or
          --  diagnose true ambiguity.
 
@@ -3037,9 +3030,7 @@ package body Sem_Ch5 is
 
       --  Subtype mark in iteration scheme
 
-      if Is_Entity_Name (R_Copy)
-        and then Is_Type (Entity (R_Copy))
-      then
+      if Is_Entity_Name (R_Copy) and then Is_Type (Entity (R_Copy)) then
          null;
 
       --  Expression in range, or Ada 2012 iterator
diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index 9ff423b..214fb11 100644
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -450,6 +450,25 @@ package body Sem_Ch8 is
    --  when compiling a subunit or instantiating a generic body on the fly,
    --  when it is necessary to save and restore full environments.
 
+   function Enclosing_Instance return Entity_Id;
+   --  In an instance nested within another one, several semantic checks are
+   --  unnecessary because the legality of the nested instance has been checked
+   --  in the enclosing generic unit. This applies in particular to legality
+   --  checks on actuals for formal subprograms of the inner instance, which
+   --  are checked as subprogram renamings, and may be complicated by confusion
+   --  in private/full views. This function returns the instance enclosing the
+   --  current one if there is such, else it returns Empty.
+   --
+   --  If the renaming determines the entity for the default of a formal
+   --  subprogram nested within another instance, choose the innermost
+   --  candidate. This is because if the formal has a box, and we are within
+   --  an enclosing instance where some candidate interpretations are local
+   --  to this enclosing instance, we know that the default was properly
+   --  resolved when analyzing the generic, so we prefer the local
+   --  candidates to those that are external. This is not always the case
+   --  but is a reasonable heuristic on the use of nested generics. The
+   --  proper solution requires a full renaming model.
+
    function Has_Implicit_Character_Literal (N : Node_Id) return Boolean;
    --  Find a type derived from Character or Wide_Character in the prefix of N.
    --  Used to resolved qualified names whose selector is a character literal.
@@ -1076,9 +1095,7 @@ package body Sem_Ch8 is
       then
          null;
 
-      elsif Ada_Version >= Ada_2005
-        and then Nkind (Nam) in N_Has_Entity
-      then
+      elsif Ada_Version >= Ada_2005 and then Nkind (Nam) in N_Has_Entity then
          declare
             Nam_Decl : Node_Id;
             Nam_Ent  : Entity_Id;
@@ -1103,7 +1120,7 @@ package body Sem_Ch8 is
                --  have a null exclusion or a null-excluding subtype.
 
                if Is_Formal_Object (Nam_Ent)
-                    and then In_Generic_Scope (Id)
+                 and then In_Generic_Scope (Id)
                then
                   if not Can_Never_Be_Null (Etype (Nam_Ent)) then
                      Error_Msg_N
@@ -1132,10 +1149,10 @@ package body Sem_Ch8 is
 
                elsif Nkind (Nam_Decl) = N_Object_Declaration
                  and then In_Instance
-                 and then Present
-                   (Corresponding_Generic_Association (Nam_Decl))
-                 and then Nkind (Expression (Nam_Decl))
-                   = N_Raise_Constraint_Error
+                 and then
+                   Present (Corresponding_Generic_Association (Nam_Decl))
+                 and then Nkind (Expression (Nam_Decl)) =
+                                            N_Raise_Constraint_Error
                then
                   Error_Msg_N
                     ("renamed actual does not exclude `NULL` "
@@ -1214,7 +1231,7 @@ package body Sem_Ch8 is
                     Nkind (Original_Node (Nam)) /= N_Attribute_Reference)
 
         or else (Nkind (Nam) = N_Type_Conversion
-                    and then Is_Tagged_Type (Entity (Subtype_Mark (Nam))))
+                  and then Is_Tagged_Type (Entity (Subtype_Mark (Nam))))
       then
          null;
 
@@ -1385,9 +1402,7 @@ package body Sem_Ch8 is
 
             begin
                E := First_Entity (Old_P);
-               while Present (E)
-                 and then E /= New_P
-               loop
+               while Present (E) and then E /= New_P loop
                   if Is_Type (E)
                     and then Nkind (Parent (E)) = N_Subtype_Declaration
                   then
@@ -1589,8 +1604,7 @@ package body Sem_Ch8 is
    begin
       if (Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Entry_Family)
         or else (Nkind (P) = N_Selected_Component
-                   and then
-                 Ekind (Entity (Selector_Name (P))) = E_Entry_Family)
+                  and then Ekind (Entity (Selector_Name (P))) = E_Entry_Family)
       then
          if Is_Entity_Name (P) then
             Old_S := Entity (P);
@@ -1982,13 +1996,11 @@ package body Sem_Ch8 is
 
          Ren_Formal := First_Formal (Ren);
          Sub_Formal := First_Formal (Sub);
-         while Present (Ren_Formal)
-           and then Present (Sub_Formal)
-         loop
+         while Present (Ren_Formal) and then Present (Sub_Formal) loop
             if Has_Null_Exclusion (Parent (Ren_Formal))
               and then
                 not (Has_Null_Exclusion (Parent (Sub_Formal))
-                       or else Can_Never_Be_Null (Etype (Sub_Formal)))
+                      or else Can_Never_Be_Null (Etype (Sub_Formal)))
             then
                Error_Msg_NE
                  ("`NOT NULL` required for parameter &",
@@ -2004,9 +2016,8 @@ package body Sem_Ch8 is
          if Nkind (Parent (Ren)) = N_Function_Specification
            and then Nkind (Parent (Sub)) = N_Function_Specification
            and then Has_Null_Exclusion (Parent (Ren))
-           and then
-             not (Has_Null_Exclusion (Parent (Sub))
-                    or else Can_Never_Be_Null (Etype (Sub)))
+           and then not (Has_Null_Exclusion (Parent (Sub))
+                          or else Can_Never_Be_Null (Etype (Sub)))
          then
             Error_Msg_N
               ("return must specify `NOT NULL`",
@@ -2081,9 +2092,7 @@ package body Sem_Ch8 is
          then
             F_Nam  := First_Entity (Entity (Nam));
             F_Spec := First_Formal (Formal_Spec);
-            while Present (F_Nam)
-              and then Present (F_Spec)
-            loop
+            while Present (F_Nam) and then Present (F_Spec) loop
                if Is_Controlling_Formal (F_Nam)
                  and then Has_Unknown_Discriminants (Etype (F_Spec))
                  and then not Is_Class_Wide_Type (Etype (F_Spec))
@@ -2114,10 +2123,8 @@ package body Sem_Ch8 is
          if Present (Alias (Subp)) then
             return Alias (Subp);
 
-         elsif
-           Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration
-             and then Present
-              (Corresponding_Body (Unit_Declaration_Node (Subp)))
+         elsif Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration
+           and then Present (Corresponding_Body (Unit_Declaration_Node (Subp)))
          then
             --  Check if renamed entity is a renaming_as_body
 
@@ -2167,7 +2174,8 @@ package body Sem_Ch8 is
          --  this must be treated as a normal attribute reference, to be
          --  expanded in subsequent instantiations.
 
-         if Is_Actual and then Is_Abstract_Subprogram (Formal_Spec)
+         if Is_Actual
+           and then Is_Abstract_Subprogram (Formal_Spec)
            and then Full_Expander_Active
          then
             declare
@@ -2382,8 +2390,8 @@ package body Sem_Ch8 is
 
             pragma Assert
               (Is_Primitive (Entity (Nam))
-                 and then
-                   Is_Abstract_Type (Find_Dispatching_Type (Entity (Nam))));
+                and then
+                  Is_Abstract_Type (Find_Dispatching_Type (Entity (Nam))));
             declare
                Old_Decl : constant Node_Id :=
                             Unit_Declaration_Node (Rename_Spec);
@@ -2490,8 +2498,7 @@ package body Sem_Ch8 is
                 (Is_Tagged_Type (T)
                   or else
                     (Is_Access_Type (T)
-                      and then
-                        Is_Tagged_Type (Designated_Type (T))))
+                      and then Is_Tagged_Type (Designated_Type (T))))
               and then Scope (Entity (Selector_Name (Nam))) /= T
             then
                Analyze_Renamed_Primitive_Operation
@@ -2506,9 +2513,7 @@ package body Sem_Ch8 is
                --  This is not allowed for renaming as body if the renamed
                --  spec is already frozen (see RM 8.5.4(5) for details).
 
-               if Present (Rename_Spec)
-                 and then Is_Frozen (Rename_Spec)
-               then
+               if Present (Rename_Spec) and then Is_Frozen (Rename_Spec) then
                   Error_Msg_N
                     ("renaming-as-body cannot rename entry as subprogram", N);
                   Error_Msg_NE
@@ -2607,9 +2612,7 @@ package body Sem_Ch8 is
          --  when performing a null exclusion check between a renaming and a
          --  renamed subprogram that has been found to be illegal.
 
-         if Ada_Version >= Ada_2005
-           and then Entity (Nam) /= Any_Id
-         then
+         if Ada_Version >= Ada_2005 and then Entity (Nam) /= Any_Id then
             Check_Null_Exclusion
               (Ren => New_S,
                Sub => Entity (Nam));
@@ -2710,13 +2713,11 @@ package body Sem_Ch8 is
 
             if CW_Actual then
                null;
-            else
+            elsif not Is_Actual or else No (Enclosing_Instance) then
                Check_Mode_Conformant (New_S, Old_S);
             end if;
 
-            if Is_Actual
-              and then Error_Posted (New_S)
-            then
+            if Is_Actual and then Error_Posted (New_S) then
                Error_Msg_NE ("invalid actual subprogram: & #!", N, Old_S);
             end if;
          end if;
@@ -2750,13 +2751,12 @@ package body Sem_Ch8 is
 
             Set_Is_Intrinsic_Subprogram
               (New_S,
-                Is_Intrinsic_Subprogram (Old_S)
-                  and then
-                    (Chars (Old_S) /= Name_Op_Ne
-                       or else Ekind (Old_S) = E_Operator
-                       or else
-                         Is_Intrinsic_Subprogram
-                            (Corresponding_Equality (Old_S))));
+               Is_Intrinsic_Subprogram (Old_S)
+                 and then
+                   (Chars (Old_S) /= Name_Op_Ne
+                     or else Ekind (Old_S) = E_Operator
+                     or else Is_Intrinsic_Subprogram
+                               (Corresponding_Equality (Old_S))));
 
             if Ekind (Alias (New_S)) = E_Operator then
                Set_Has_Delayed_Freeze (New_S, False);
@@ -2909,7 +2909,6 @@ package body Sem_Ch8 is
                F1 := First_Formal (Candidate_Renaming);
                F2 := First_Formal (New_S);
                T1 := First_Subtype (Etype (F1));
-
                while Present (F1) and then Present (F2) loop
                   Next_Formal (F1);
                   Next_Formal (F2);
@@ -2980,9 +2979,8 @@ package body Sem_Ch8 is
 
       if Comes_From_Source (N)
         and then Present (Old_S)
-        and then
-          (Nkind (Old_S) = N_Defining_Operator_Symbol
-            or else Ekind (Old_S) = E_Operator)
+        and then (Nkind (Old_S) = N_Defining_Operator_Symbol
+                   or else Ekind (Old_S) = E_Operator)
         and then Nkind (New_S) = N_Defining_Operator_Symbol
         and then Chars (Old_S) /= Chars (New_S)
       then
@@ -3003,9 +3001,8 @@ package body Sem_Ch8 is
         and then Comes_From_Source (N)
         and then Scope (Old_S) /= Standard_Standard
         and then Warn_On_Redundant_Constructs
-        and then
-          (Is_Immediately_Visible (Old_S)
-            or else Is_Potentially_Use_Visible (Old_S))
+        and then (Is_Immediately_Visible (Old_S)
+                   or else Is_Potentially_Use_Visible (Old_S))
         and then Is_Overloadable (Current_Scope)
         and then Chars (Current_Scope) /= Chars (Old_S)
       then
@@ -3102,9 +3099,7 @@ package body Sem_Ch8 is
          if Is_Entity_Name (Pack_Name) then
             Pack := Entity (Pack_Name);
 
-            if Ekind (Pack) /= E_Package
-              and then Etype (Pack) /= Any_Type
-            then
+            if Ekind (Pack) /= E_Package and then Etype (Pack) /= Any_Type then
                if Ekind (Pack) = E_Generic_Package then
                   Error_Msg_N  -- CODEFIX
                    ("a generic package is not allowed in a use clause",
@@ -3224,14 +3219,12 @@ package body Sem_Ch8 is
                   function Mentioned (Nam : Node_Id) return Boolean is
                   begin
                      return Nkind (Name (Item)) = N_Selected_Component
-                              and then
-                            Chars (Prefix (Name (Item))) = Chars (Nam);
+                       and then Chars (Prefix (Name (Item))) = Chars (Nam);
                   end Mentioned;
 
                begin
                   Pref := Prefix (Id);
                   Item := First (Context_Items (Parent (N)));
-
                   while Present (Item) and then Item /= N loop
                      if Nkind (Item) = N_With_Clause
                        and then Limited_Present (Item)
@@ -3260,9 +3253,7 @@ package body Sem_Ch8 is
 
    begin
       if In_Open_Scopes (Pack) then
-         if Warn_On_Redundant_Constructs
-           and then Pack = Current_Scope
-         then
+         if Warn_On_Redundant_Constructs and then Pack = Current_Scope then
             Error_Msg_NE -- CODEFIX
               ("& is already use-visible within itself?r?", Pack_Name, Pack);
          end if;
@@ -3572,9 +3563,7 @@ package body Sem_Ch8 is
       Old_S  : Entity_Id;
 
    begin
-      if Is_Frozen (Subp)
-        and then not Has_Completion (Subp)
-      then
+      if Is_Frozen (Subp) and then not Has_Completion (Subp) then
          B_Node :=
            Build_Renamed_Body
              (Parent (Declaration_Node (Subp)), Defining_Entity (N));
@@ -3591,12 +3580,10 @@ package body Sem_Ch8 is
                Analyze (B_Node);
             end if;
 
-            if Is_Intrinsic_Subprogram (Old_S)
-              and then not In_Instance
-            then
+            if Is_Intrinsic_Subprogram (Old_S) and then not In_Instance then
                Error_Msg_N
                  ("subprogram used in renaming_as_body cannot be intrinsic",
-                    Name (N));
+                  Name (N));
             end if;
 
          else
@@ -3629,11 +3616,10 @@ package body Sem_Ch8 is
       --  for details on their handling.
 
       elsif Is_Concurrent_Type (Scope (E)) then
-
          P := Parent (N);
          while Present (P)
            and then not Nkind_In (P, N_Parameter_Specification,
-                                  N_Component_Declaration)
+                                     N_Component_Declaration)
          loop
             P := Parent (P);
          end loop;
@@ -3670,13 +3656,10 @@ package body Sem_Ch8 is
 
    begin
       Item := First (Context_Items (Parent (N)));
-
-      while Present (Item)
-        and then Item /= N
-      loop
+      while Present (Item) and then Item /= N loop
          if Nkind (Item) = N_With_Clause
 
-            --  Protect the frontend against previous critical errors
+           --  Protect the frontend against previous critical errors
 
            and then Nkind (Name (Item)) /= N_Selected_Component
            and then Entity (Name (Item)) = Pack
@@ -3745,9 +3728,9 @@ package body Sem_Ch8 is
            ("renamed unit must be a child unit of generic parent", Name (N));
 
       elsif Nkind (N) in N_Generic_Renaming_Declaration
-         and then  Nkind (Name (N)) = N_Expanded_Name
-         and then Is_Generic_Instance (Entity (Prefix (Name (N))))
-         and then Is_Generic_Unit (Old_E)
+        and then  Nkind (Name (N)) = N_Expanded_Name
+        and then Is_Generic_Instance (Entity (Prefix (Name (N))))
+        and then Is_Generic_Unit (Old_E)
       then
          Error_Msg_N
            ("renamed generic unit must be a library unit", Name (N));
@@ -3766,6 +3749,30 @@ package body Sem_Ch8 is
       end if;
    end Check_Library_Unit_Renaming;
 
+   ------------------------
+   -- Enclosing_Instance --
+   ------------------------
+
+   function Enclosing_Instance return Entity_Id is
+      S : Entity_Id;
+
+   begin
+      if not Is_Generic_Instance (Current_Scope) then
+         return Empty;
+      end if;
+
+      S := Scope (Current_Scope);
+      while S /= Standard_Standard loop
+         if Is_Generic_Instance (S) then
+            return S;
+         end if;
+
+         S := Scope (S);
+      end loop;
+
+      return Empty;
+   end Enclosing_Instance;
+
    ---------------
    -- End_Scope --
    ---------------
@@ -3952,16 +3959,14 @@ package body Sem_Ch8 is
 
                   if Nkind (Id) = N_Defining_Operator_Symbol
                        and then
-                         (Is_Primitive_Operator_In_Use
-                           (Id, First_Formal (Id))
-                            or else
-                          (Present (Next_Formal (First_Formal (Id)))
-                             and then
-                               Is_Primitive_Operator_In_Use
-                                 (Id, Next_Formal (First_Formal (Id)))))
+                         (Is_Primitive_Operator_In_Use (Id, First_Formal (Id))
+                           or else
+                             (Present (Next_Formal (First_Formal (Id)))
+                               and then
+                                 Is_Primitive_Operator_In_Use
+                                   (Id, Next_Formal (First_Formal (Id)))))
                   then
                      null;
-
                   else
                      Set_Is_Potentially_Use_Visible (Id, False);
                   end if;
@@ -4222,10 +4227,10 @@ package body Sem_Ch8 is
            Nkind (N) = N_Identifier
              and then
                (Nkind (Parent (N)) = N_Procedure_Call_Statement
-                  or else
-                    (Nkind (Parent (N)) = N_Parameter_Association
-                       and then N = Explicit_Actual_Parameter (Parent (N))
-                       and then Nkind (Parent (Parent (N))) =
+                 or else
+                   (Nkind (Parent (N)) = N_Parameter_Association
+                     and then N = Explicit_Actual_Parameter (Parent (N))
+                     and then Nkind (Parent (Parent (N))) =
                                           N_Procedure_Call_Statement));
       end Is_Actual_Parameter;
 
@@ -4802,9 +4807,7 @@ package body Sem_Ch8 is
                --  Find current instance
 
                Inst := Current_Scope;
-               while Present (Inst)
-                 and then Inst /= Standard_Standard
-               loop
+               while Present (Inst) and then Inst /= Standard_Standard loop
                   if Is_Generic_Instance (Inst) then
                      exit;
                   end if;
@@ -5202,9 +5205,7 @@ package body Sem_Ch8 is
       end;
 
       if No (Id)
-        and then (Ekind (P_Name) = E_Procedure
-                    or else
-                  Ekind (P_Name) = E_Function)
+        and then Ekind_In (P_Name, E_Procedure, E_Function)
         and then Is_Generic_Instance (P_Name)
       then
          --  Expanded name denotes entity in (instance of) generic subprogram.
@@ -5463,9 +5464,7 @@ package body Sem_Ch8 is
 
       --  Ada 2005 (AI-50217): Check usage of entities in limited withed units
 
-      if Ekind (P_Name) = E_Package
-        and then From_With_Type (P_Name)
-      then
+      if Ekind (P_Name) = E_Package and then From_With_Type (P_Name) then
          if From_With_Type (Id)
            or else Is_Type (Id)
            or else Ekind (Id) = E_Package
@@ -5481,11 +5480,11 @@ package body Sem_Ch8 is
 
       if Is_Task_Type (P_Name)
         and then ((Ekind (Id) = E_Entry
-                     and then Nkind (Parent (N)) /= N_Attribute_Reference)
+                    and then Nkind (Parent (N)) /= N_Attribute_Reference)
                    or else
-                    (Ekind (Id) = E_Entry_Family
-                      and then
-                        Nkind (Parent (Parent (N))) /= N_Attribute_Reference))
+                     (Ekind (Id) = E_Entry_Family
+                       and then
+                         Nkind (Parent (Parent (N))) /= N_Attribute_Reference))
       then
          --  If both the task type and the entry are in scope, this may still
          --  be the expanded name of an entry formal.
@@ -5538,18 +5537,15 @@ package body Sem_Ch8 is
       if Ekind (Id) = E_Void then
          Premature_Usage (N);
 
-      elsif Is_Overloadable (Id)
-        and then Present (Homonym (Id))
-      then
+      elsif Is_Overloadable (Id) and then Present (Homonym (Id)) then
          declare
             H : Entity_Id := Homonym (Id);
 
          begin
             while Present (H) loop
                if Scope (H) = Scope (Id)
-                 and then
-                   (not Is_Hidden (H)
-                      or else Is_Immediately_Visible (H))
+                 and then (not Is_Hidden (H)
+                            or else Is_Immediately_Visible (H))
                then
                   Collect_Interps (N);
                   exit;
@@ -5618,17 +5614,6 @@ package body Sem_Ch8 is
       Old_S : Entity_Id;
       Inst  : Entity_Id;
 
-      function Enclosing_Instance return Entity_Id;
-      --  If the renaming determines the entity for the default of a formal
-      --  subprogram nested within another instance, choose the innermost
-      --  candidate. This is because if the formal has a box, and we are within
-      --  an enclosing instance where some candidate interpretations are local
-      --  to this enclosing instance, we know that the default was properly
-      --  resolved when analyzing the generic, so we prefer the local
-      --  candidates to those that are external. This is not always the case
-      --  but is a reasonable heuristic on the use of nested generics. The
-      --  proper solution requires a full renaming model.
-
       function Is_Visible_Operation (Op : Entity_Id) return Boolean;
       --  If the renamed entity is an implicit operator, check whether it is
       --  visible because its operand type is properly visible. This check
@@ -5644,32 +5629,6 @@ package body Sem_Ch8 is
       --  Determine whether a candidate subprogram is defined within the
       --  enclosing instance. If yes, it has precedence over outer candidates.
 
-      ------------------------
-      -- Enclosing_Instance --
-      ------------------------
-
-      function Enclosing_Instance return Entity_Id is
-         S : Entity_Id;
-
-      begin
-         if not Is_Generic_Instance (Current_Scope)
-           and then not Is_Actual
-         then
-            return Empty;
-         end if;
-
-         S := Scope (Current_Scope);
-         while S /= Standard_Standard loop
-            if Is_Generic_Instance (S) then
-               return S;
-            end if;
-
-            S := Scope (S);
-         end loop;
-
-         return Empty;
-      end Enclosing_Instance;
-
       --------------------------
       -- Is_Visible_Operation --
       --------------------------
@@ -5683,9 +5642,8 @@ package body Sem_Ch8 is
          if Ekind (Op) /= E_Operator
            or else Scope (Op) /= Standard_Standard
            or else (In_Instance
-                      and then
-                        (not Is_Actual
-                           or else Present (Enclosing_Instance)))
+                     and then (not Is_Actual
+                                or else Present (Enclosing_Instance)))
          then
             return True;
 
@@ -5776,7 +5734,10 @@ package body Sem_Ch8 is
       Candidate_Renaming := Empty;
 
       if not Is_Overloaded (Nam) then
-         if Entity_Matches_Spec (Entity (Nam), New_S) then
+         if Is_Actual and then Present (Enclosing_Instance) then
+            Old_S := Entity (Nam);
+
+         elsif Entity_Matches_Spec (Entity (Nam), New_S) then
             Candidate_Renaming := New_S;
 
             if Is_Visible_Operation (Entity (Nam)) then
@@ -5786,8 +5747,8 @@ package body Sem_Ch8 is
          elsif
            Present (First_Formal (Entity (Nam)))
              and then Present (First_Formal (New_S))
-             and then (Base_Type (Etype (First_Formal (Entity (Nam))))
-                        = Base_Type (Etype (First_Formal (New_S))))
+             and then (Base_Type (Etype (First_Formal (Entity (Nam)))) =
+                       Base_Type (Etype (First_Formal (New_S))))
          then
             Candidate_Renaming := Entity (Nam);
          end if;
@@ -5851,8 +5812,8 @@ package body Sem_Ch8 is
             elsif
               Present (First_Formal (It.Nam))
                 and then Present (First_Formal (New_S))
-                and then  (Base_Type (Etype (First_Formal (It.Nam)))
-                            = Base_Type (Etype (First_Formal (New_S))))
+                and then (Base_Type (Etype (First_Formal (It.Nam))) =
+                          Base_Type (Etype (First_Formal (New_S))))
             then
                Candidate_Renaming := It.Nam;
             end if;
@@ -5964,10 +5925,10 @@ package body Sem_Ch8 is
                       ((RTE_Available (RE_Dispatch_Table_Wrapper)
                          and then Scope (Selector) =
                                      RTE (RE_Dispatch_Table_Wrapper))
-                          or else
-                       (RTE_Available (RE_No_Dispatch_Table_Wrapper)
-                         and then Scope (Selector) =
-                                     RTE (RE_No_Dispatch_Table_Wrapper)))
+                         or else
+                           (RTE_Available (RE_No_Dispatch_Table_Wrapper)
+                             and then Scope (Selector) =
+                                        RTE (RE_No_Dispatch_Table_Wrapper)))
                   then
                      C_Etype := Empty;
 
@@ -6071,7 +6032,7 @@ package body Sem_Ch8 is
          elsif Is_Appropriate_For_Entry_Prefix (P_Type)
            and then not In_Open_Scopes (P_Name)
            and then (not Is_Concurrent_Type (Etype (P_Name))
-                       or else not In_Open_Scopes (Etype (P_Name)))
+                      or else not In_Open_Scopes (Etype (P_Name)))
          then
             --  Call to protected operation or entry. Type checking is
             --  needed on the prefix.
@@ -6148,9 +6109,9 @@ package body Sem_Ch8 is
                --  entry, as is P.X; this is an error.
 
                if Ekind (P_Name) /= E_Function
-                 and then (not Is_Overloaded (P)
-                             or else
-                           Nkind (Parent (N)) = N_Procedure_Call_Statement)
+                 and then
+                   (not Is_Overloaded (P)
+                     or else Nkind (Parent (N)) = N_Procedure_Call_Statement)
                then
                   --  Prefix may mention a package that is hidden by a local
                   --  declaration: let the user know. Scan the full homonym
@@ -6327,9 +6288,7 @@ package body Sem_Ch8 is
                      --  Warn_On_Obsolescent_ Feature). Once this issue
                      --  is cleared in the sources, it can be enabled.
 
-                     elsif Warn_On_Obsolescent_Feature
-                       and then False
-                     then
+                     elsif Warn_On_Obsolescent_Feature and then False then
                         Error_Msg_N
                           ("applying 'Class to an untagged incomplete type"
                            & " is an obsolescent feature (RM J.11)?r?", N);
@@ -6596,9 +6555,7 @@ package body Sem_Ch8 is
       Priv_Id : Entity_Id := Empty;
 
    begin
-      if Ekind (P) = E_Package
-        and then not In_Open_Scopes (P)
-      then
+      if Ekind (P) = E_Package and then not In_Open_Scopes (P) then
          Priv_Id := First_Private_Entity (P);
       end if;
 
@@ -6611,9 +6568,7 @@ package body Sem_Ch8 is
       end if;
 
       Id := First_Entity (P);
-      while Present (Id)
-        and then Id /= Priv_Id
-      loop
+      while Present (Id) and then Id /= Priv_Id loop
          if Is_Standard_Character_Type (Id) and then Is_Base_Type (Id) then
 
             --  We replace the node with the literal itself, resolve as a
@@ -6695,7 +6650,6 @@ package body Sem_Ch8 is
 
       begin
          Predef_Op := Current_Entity (Selector_Name (N));
-
          while Present (Predef_Op)
            and then Scope (Predef_Op) /= Standard_Standard
          loop
@@ -6760,9 +6714,7 @@ package body Sem_Ch8 is
    --  Start of processing for Has_Implicit_Operator
 
    begin
-      if Ekind (P) = E_Package
-        and then not In_Open_Scopes (P)
-      then
+      if Ekind (P) = E_Package and then not In_Open_Scopes (P) then
          Priv_Id := First_Private_Entity (P);
       end if;
 
@@ -7202,9 +7154,7 @@ package body Sem_Ch8 is
                   --  of the stack is related to the current compilation.
 
                   Scop := Current_Scope;
-                  while Present (Scop)
-                    and then Scop /= Standard_Standard
-                  loop
+                  while Present (Scop) and then Scop /= Standard_Standard loop
                      if Is_Compilation_Unit (Scop)
                        and then not Is_Child_Unit (Scop)
                      then
@@ -7495,14 +7445,9 @@ package body Sem_Ch8 is
       --  name resolution on component associations. (see 4717-008). In such a
       --  case, look for the visible homonym on the chain.
 
-      if In_Instance
-        and then Present (Homonym (E))
-      then
+      if In_Instance and then Present (Homonym (E)) then
          E := Homonym (E);
-
-         while Present (E)
-           and then not In_Open_Scopes (Scope (E))
-         loop
+         while Present (E) and then not In_Open_Scopes (Scope (E)) loop
             E := Homonym (E);
          end loop;
 
@@ -7609,16 +7554,14 @@ package body Sem_Ch8 is
          if No (With_Sys)
            and then
              (Nkind (The_Unit) = N_Package_Body
-                or else (Nkind (The_Unit) = N_Subprogram_Body
-                           and then
-                             not Acts_As_Spec (Cunit (Current_Sem_Unit))))
+               or else (Nkind (The_Unit) = N_Subprogram_Body
+                         and then not Acts_As_Spec (Cunit (Current_Sem_Unit))))
          then
             With_Sys := Find_System (Library_Unit (Cunit (Current_Sem_Unit)));
          end if;
 
-         if No (With_Sys)
-           and then Present (N)
-         then
+         if No (With_Sys) and then Present (N) then
+
             --  If we are compiling a subunit, we need to examine its
             --  context as well (Current_Sem_Unit is the parent unit);
 
@@ -7735,8 +7678,9 @@ package body Sem_Ch8 is
                   else
                      pragma Assert
                        (Nkind (Parent (E)) = N_Defining_Program_Unit_Name
-                          and then
-                        Nkind (Parent (Parent (E))) = N_Package_Specification);
+                         and then
+                           Nkind (Parent (Parent (E))) =
+                                               N_Package_Specification);
                      Set_Is_Immediately_Visible (E,
                        Limited_View_Installed (Parent (Parent (E))));
                   end if;
@@ -7746,9 +7690,8 @@ package body Sem_Ch8 is
 
                Next_Entity (E);
 
-               if not Full_Vis
-                 and then Is_Package_Or_Generic_Package (S)
-               then
+               if not Full_Vis and then Is_Package_Or_Generic_Package (S) then
+
                   --  We are in the visible part of the package scope
 
                   exit when E = First_Private_Entity (S);
@@ -7798,8 +7741,7 @@ package body Sem_Ch8 is
             elsif Is_Hidden_Open_Scope (S) then
                null;
 
-            elsif (Ekind (S) = E_Procedure
-                    or else Ekind (S) = E_Function)
+            elsif Ekind_In (S, E_Procedure, E_Function)
               and then Has_Completion (S)
             then
                Full_Vis := True;
@@ -7974,7 +7916,7 @@ package body Sem_Ch8 is
       Id := First_Entity (P);
       while Present (Id)
         and then (Id /= First_Private_Entity (P)
-                    or else Private_With_OK) -- Ada 2005 (AI-262)
+                   or else Private_With_OK) -- Ada 2005 (AI-262)
       loop
          Prev := Current_Entity (Id);
          while Present (Prev) loop
@@ -8042,10 +7984,10 @@ package body Sem_Ch8 is
             elsif Ekind (Prev) = E_Operator
               and then Operator_Matches_Spec (Prev, Id)
               and then In_Open_Scopes
-               (Scope (Base_Type (Etype (First_Formal (Id)))))
+                         (Scope (Base_Type (Etype (First_Formal (Id)))))
               and then (No (Next_Formal (First_Formal (Id)))
-                         or else Etype (First_Formal (Id))
-                           = Etype (Next_Formal (First_Formal (Id)))
+                         or else Etype (First_Formal (Id)) =
+                                 Etype (Next_Formal (First_Formal (Id)))
                          or else Chars (Prev) = Name_Op_Expon)
             then
                goto Next_Usable_Entity;
@@ -8074,14 +8016,11 @@ package body Sem_Ch8 is
          --  On exit, we know entity is not hidden, unless it is private
 
          if not Is_Hidden (Id)
-           and then ((not Is_Child_Unit (Id))
-                       or else Is_Visible_Lib_Unit (Id))
+           and then ((not Is_Child_Unit (Id)) or else Is_Visible_Lib_Unit (Id))
          then
             Set_Is_Potentially_Use_Visible (Id);
 
-            if Is_Private_Type (Id)
-              and then Present (Full_View (Id))
-            then
+            if Is_Private_Type (Id) and then Present (Full_View (Id)) then
                Set_Is_Potentially_Use_Visible (Full_View (Id));
             end if;
          end if;
@@ -8252,12 +8191,10 @@ package body Sem_Ch8 is
       --  a limited view unless we only have a limited view of its enclosing
       --  package.
 
-      elsif From_With_Type (T)
-        and then From_With_Type (Scope (T))
-      then
+      elsif From_With_Type (T) and then From_With_Type (Scope (T)) then
          Error_Msg_N
            ("incomplete type from limited view "
-             & "cannot appear in use clause", Id);
+            & "cannot appear in use clause", Id);
 
       --  If the subtype mark designates a subtype in a different package,
       --  we have to check that the parent type is visible, otherwise the
@@ -8321,18 +8258,18 @@ package body Sem_Ch8 is
       if Warn_On_Redundant_Constructs
         and then Is_Known_Used
 
-         --                     with P;         with P; use P;
-         --    package P is     package X is    package body X is
-         --       type T ...       use P.T;
+        --                     with P;         with P; use P;
+        --    package P is     package X is    package body X is
+        --       type T ...       use P.T;
 
-         --  The compilation unit is the body of X. GNAT first compiles the
-         --  spec of X, then proceeds to the body. At that point P is marked
-         --  as use visible. The analysis then reinstalls the spec along with
-         --  its context. The use clause P.T is now recognized as redundant,
-         --  but in the wrong context. Do not emit a warning in such cases.
-         --  Do not emit a warning either if we are in an instance, there is
-         --  no redundancy between an outer use_clause and one that appears
-         --  within the generic.
+        --  The compilation unit is the body of X. GNAT first compiles the
+        --  spec of X, then proceeds to the body. At that point P is marked
+        --  as use visible. The analysis then reinstalls the spec along with
+        --  its context. The use clause P.T is now recognized as redundant,
+        --  but in the wrong context. Do not emit a warning in such cases.
+        --  Do not emit a warning either if we are in an instance, there is
+        --  no redundancy between an outer use_clause and one that appears
+        --  within the generic.
 
         and then not Spec_Reloaded_For_Body
         and then not In_Instance
@@ -8386,7 +8323,6 @@ package body Sem_Ch8 is
                        and then
                      Nkind (Parent (Clause2)) = N_Compilation_Unit
                   then
-
                      --  If the unit is a subprogram body that acts as spec,
                      --  the context clause is shared with the constructed
                      --  subprogram spec. Clearly there is no redundancy.