[COMMITTED] ada: Reject non-statically compatible extended return statement
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Commit Message
From: Javier Miranda <miranda@adacore.com>
Add missing check of RM 6.5(5.3/5): when the result subtype of the
function is defined by a subtype mark, the subtype defined by the
subtype indication of the extended return statement shall be
statically compatible with the result subtype of the function.
gcc/ada/
* sem_ch3.adb (Check_Return_Subtype_Indication): Add missing check
on statically compatible subtypes.
* sem_eval.adb (Subtypes_Statically_Compatible): Ensure that both
types are either scalar types or access types to evaluate this
predicate.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_ch3.adb | 25 +++++++++++++++++++++++++
gcc/ada/sem_eval.adb | 4 ++--
2 files changed, 27 insertions(+), 2 deletions(-)
@@ -4129,6 +4129,31 @@ package body Sem_Ch3 is
if not Subtypes_Statically_Match (Obj_Typ, R_Typ) then
Error_No_Match (Indic);
end if;
+
+ -- If the result subtype of the function is defined by a
+ -- subtype_mark, the return_subtype_indication shall be a
+ -- subtype_indication. The subtype defined by the subtype_
+ -- indication shall be statically compatible with the result
+ -- subtype of the function (RM 6.5(5.3/5)).
+
+ -- We exclude the extended return statement of the predefined
+ -- stream input to avoid reporting spurious errors, because its
+ -- code is expanded on the basis of the base type (see subprogram
+ -- Stream_Base_Type).
+
+ elsif Nkind (Indic) = N_Subtype_Indication
+ and then not Subtypes_Statically_Compatible (Obj_Typ, R_Typ)
+ and then not Is_TSS (Func_Id, TSS_Stream_Input)
+ then
+ Error_Msg_N
+ ("result subtype must be statically compatible with the " &
+ "function result type", Indic);
+
+ if not Predicates_Compatible (Obj_Typ, R_Typ) then
+ Error_Msg_NE
+ ("\predicate on result subtype is not compatible with &",
+ Indic, R_Typ);
+ end if;
end if;
-- All remaining cases are illegal
@@ -6507,7 +6507,7 @@ package body Sem_Eval is
-- Scalar types
- elsif Is_Scalar_Type (T1) then
+ elsif Is_Scalar_Type (T1) and then Is_Scalar_Type (T2) then
-- Definitely compatible if we match
@@ -6560,7 +6560,7 @@ package body Sem_Eval is
-- Access types
- elsif Is_Access_Type (T1) then
+ elsif Is_Access_Type (T1) and then Is_Access_Type (T2) then
return
(not Is_Constrained (T2)
or else Subtypes_Statically_Match