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authorEd Schonberg <schonberg@adacore.com>2021-01-14 17:54:05 -0500
committerPierre-Marie de Rodat <derodat@adacore.com>2021-05-06 03:51:20 -0400
commitc2f94a898f16d790e21533a6e0d345c23dd379a0 (patch)
treeb8670e74409b7cff80753b552d4c1ecb292f6769
parentafab03da75f6b5e11087738d71aeb8c3efa40f1c (diff)
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[Ada] Crash on if_expression used as index of discriminant-dependent array
gcc/ada/ * sem_res.adb (Resolve_If_Expression): If the context of the expression is an indexed_component, resolve the expression and its dependent_expressions with the base type of the index, to ensure that an index check is generated when resolving the enclosing indexxed_component, and avoid an improper use of discriminants out of scope, when the index type is discriminant-dependent.
-rw-r--r--gcc/ada/sem_res.adb28
1 files changed, 22 insertions, 6 deletions
diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
index 77af6ce..88d294e 100644
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -9095,6 +9095,16 @@ package body Sem_Res is
-- that the context in general allows sliding, while a qualified
-- expression forces equality of bounds.
+ Result_Type : Entity_Id := Typ;
+ -- So in most cases the type of the If_Expression and of its
+ -- dependent expressions is that of the context. However, if
+ -- the expression is the index of an Indexed_Component, we must
+ -- ensure that a proper index check is applied, rather than a
+ -- range check on the index type (which might be discriminant
+ -- dependent). In this case we resolve with the base type of the
+ -- index type, and the index check is generated in the resolution
+ -- of the indexed_component above.
+
-----------------
-- Apply_Check --
-----------------
@@ -9118,10 +9128,10 @@ package body Sem_Res is
else
Rewrite (Expr,
Make_Qualified_Expression (Loc,
- Subtype_Mark => New_Occurrence_Of (Typ, Loc),
+ Subtype_Mark => New_Occurrence_Of (Result_Type, Loc),
Expression => Relocate_Node (Expr)));
- Analyze_And_Resolve (Expr, Typ);
+ Analyze_And_Resolve (Expr, Result_Type);
end if;
end Apply_Check;
@@ -9140,6 +9150,12 @@ package body Sem_Res is
return;
end if;
+ if Nkind (Parent (N)) = N_Indexed_Component
+ or else Nkind (Parent (Parent (N))) = N_Indexed_Component
+ then
+ Result_Type := Base_Type (Typ);
+ end if;
+
Then_Expr := Next (Condition);
if No (Then_Expr) then
@@ -9149,7 +9165,7 @@ package body Sem_Res is
Else_Expr := Next (Then_Expr);
Resolve (Condition, Any_Boolean);
- Resolve (Then_Expr, Typ);
+ Resolve (Then_Expr, Result_Type);
Apply_Check (Then_Expr);
-- If ELSE expression present, just resolve using the determined type
@@ -9163,7 +9179,7 @@ package body Sem_Res is
Resolve (Else_Expr, Any_Real);
else
- Resolve (Else_Expr, Typ);
+ Resolve (Else_Expr, Result_Type);
end if;
Apply_Check (Else_Expr);
@@ -9187,7 +9203,7 @@ package body Sem_Res is
elsif Root_Type (Typ) = Standard_Boolean then
Else_Expr :=
Convert_To (Typ, New_Occurrence_Of (Standard_True, Sloc (N)));
- Analyze_And_Resolve (Else_Expr, Typ);
+ Analyze_And_Resolve (Else_Expr, Result_Type);
Append_To (Expressions (N), Else_Expr);
else
@@ -9195,7 +9211,7 @@ package body Sem_Res is
Append_To (Expressions (N), Error);
end if;
- Set_Etype (N, Typ);
+ Set_Etype (N, Result_Type);
if not Error_Posted (N) then
Eval_If_Expression (N);