[Ada] Enforce deferred constant completion rules
If a constrained subtype is given when a deferred constant is declared,
then the subtype given in the completion is required (at compile time)
to be subject to a statically matching constraint. This rule was not
properly enforced in some cases and constructs that should have been
rejected were incorrectly accepted.
gcc/ada/
* sem_ch3.adb (Check_Possible_Deferred_Completion): Delete
Prev_Obj_Def formal parameter. Reorganize code so that
statically matching check is also performed in the case where
the subtype given in the initial declaration is constrained and
the subtype given in the completion is not.
diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
index 84971e3..93aa2ca 100644
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -13126,7 +13126,6 @@
procedure Check_Possible_Deferred_Completion
(Prev_Id : Entity_Id;
- Prev_Obj_Def : Node_Id;
Curr_Obj_Def : Node_Id);
-- Determine whether the two object definitions describe the partial
-- and the full view of a constrained deferred constant. Generate
@@ -13146,15 +13145,16 @@
procedure Check_Possible_Deferred_Completion
(Prev_Id : Entity_Id;
- Prev_Obj_Def : Node_Id;
Curr_Obj_Def : Node_Id)
is
+ Curr_Typ : Entity_Id;
+ Prev_Typ : constant Entity_Id := Etype (Prev_Id);
+ Anon_Acc : constant Boolean := Is_Anonymous_Access_Type (Prev_Typ);
+ Mismatch : Boolean := False;
begin
- if Nkind (Prev_Obj_Def) = N_Subtype_Indication
- and then Present (Constraint (Prev_Obj_Def))
- and then Nkind (Curr_Obj_Def) = N_Subtype_Indication
- and then Present (Constraint (Curr_Obj_Def))
- then
+ if Anon_Acc then
+ null;
+ elsif Nkind (Curr_Obj_Def) = N_Subtype_Indication then
declare
Loc : constant Source_Ptr := Sloc (N);
Def_Id : constant Entity_Id := Make_Temporary (Loc, 'S');
@@ -13167,13 +13167,32 @@
begin
Insert_Before_And_Analyze (N, Decl);
Set_Etype (Id, Def_Id);
-
- if not Subtypes_Statically_Match (Etype (Prev_Id), Def_Id) then
- Error_Msg_Sloc := Sloc (Prev_Id);
- Error_Msg_N ("subtype does not statically match deferred "
- & "declaration #", N);
- end if;
+ Curr_Typ := Def_Id;
end;
+ else
+ Curr_Typ := Etype (Curr_Obj_Def);
+ end if;
+
+ if Anon_Acc then
+ if Nkind (Curr_Obj_Def) /= N_Access_Definition then
+ Mismatch := True;
+ elsif Has_Null_Exclusion (Prev_Typ)
+ and then not Null_Exclusion_Present (Curr_Obj_Def)
+ then
+ Mismatch := True;
+ end if;
+ -- ??? Another check needed: mismatch if disagreement
+ -- between designated types/profiles .
+ else
+ Mismatch :=
+ Is_Constrained (Prev_Typ)
+ and then not Subtypes_Statically_Match (Prev_Typ, Curr_Typ);
+ end if;
+
+ if Mismatch then
+ Error_Msg_Sloc := Sloc (Prev_Id);
+ Error_Msg_N ("subtype does not statically match deferred "
+ & "declaration #", N);
end if;
end Check_Possible_Deferred_Completion;
@@ -13316,7 +13335,6 @@
Check_Possible_Deferred_Completion
(Prev_Id => Prev,
- Prev_Obj_Def => Object_Definition (Parent (Prev)),
Curr_Obj_Def => Obj_Def);
Set_Full_View (Prev, Id);
