[Bug ada/116945] Valgrind reports uninitialized memory use in sem_ch12.adb (sem_ch12__instance_context__save_and_reset)

[ebotcazou at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116945

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |WONTFIX
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |ebotcazou at gcc dot gnu.org

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
It's a call to 'Valid, which is precisely designed for this case:

                  --  If we have called Increment_Last but have not yet
                  --  initialized the new last element of the table, then
                  --  that last element might be invalid. Saving and
                  --  restoring (especially restoring, it turns out) invalid
                  --  values can result in exceptions if predicate checking
                  --  is enabled, so replace invalid values with Empty.

                  if Indexed_Assoc.Gen_Id'Valid then
                     Result_Pair.Formal_Id := Indexed_Assoc.Gen_Id;
                  else
                     pragma Assert (Index = Result'Last);
                     Result_Pair.Formal_Id := Empty;
                  end if;

                  if Indexed_Assoc.Act_Id'Valid then
                     Result_Pair.Actual_Id := Indexed_Assoc.Act_Id;
                  else
                     pragma Assert (Index = Result'Last);
                     Result_Pair.Actual_Id := Empty;
                  end if;