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[Ada] Crash on if_expression used as index of discriminant-dependent array

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	* 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.
This commit is contained in:
Ed Schonberg 2021-01-14 17:54:05 -05:00 committed by Pierre-Marie de Rodat
parent afab03da75
commit c2f94a898f
1 changed files with 22 additions and 6 deletions
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28
gcc/ada/sem_res.adb
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@ -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);