From: Bob Duff <d...@adacore.com>
Follow-on to previous change "Disable self-referential with_clauses",
which caused some regressions. Remove useless use clauses referring
to useless self-referential with'ed packages. This is necessary
because in some cases, such use clauses cause the compiler to
crash or give spurious errors.
In addition, enable the warning on self-referential with_clauses.
gcc/ada/ChangeLog:
* sem_ch10.adb (Analyze_With_Clause): In the case of a
self-referential with clause, if there is a subsequent use clause
for the same package (which is necessarily useless), remove it from
the context clause. Reenable the warning.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_ch10.adb | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/gcc/ada/sem_ch10.adb b/gcc/ada/sem_ch10.adb
index 202a44eb87c..4e582440c40 100644
--- a/gcc/ada/sem_ch10.adb
+++ b/gcc/ada/sem_ch10.adb
@@ -3039,11 +3039,32 @@ package body Sem_Ch10 is
-- Self-referential withs are always useless, so warn
- if Warn_On_Redundant_Constructs and then False then -- ???
- -- Disable for now, because it breaks SPARK builds
+ if Warn_On_Redundant_Constructs then
Error_Msg_N ("unnecessary with of self?r?", N);
end if;
+ declare
+ This : Node_Id := Next (N);
+ begin
+ -- Remove subsequent use clauses for the same package
+
+ while Present (This) loop
+ declare
+ Nxt : constant Node_Id := Next (This);
+ begin
+ if Nkind (This) = N_Use_Package_Clause
+ and then Same_Name (Name (N), Name (This))
+ then
+ if not More_Ids (This) and not Prev_Ids (This) then
+ Remove (This);
+ end if;
+ end if;
+
+ This := Nxt;
+ end;
+ end loop;
+ end;
+
-- Normal (non-self-referential) case
else
--
2.43.0
