[Bug ada/18765] illegal program not detected, "/=" when "=" is ambiguous

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18765

--- Comment #6 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
The key is of course the declaration of the "boolean" subtype, so probably:

diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
index 8cf191d751b..9c02ad6ff4f 100644
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -12860,7 +12860,7 @@ package body Sem_Ch6 is

       <<Check_Inequality>>
          if Chars (S) = Name_Op_Eq
-           and then Etype (S) = Standard_Boolean
+           and then Base_Type (Etype (S)) = Standard_Boolean
            and then Present (Parent (S))
            and then not Is_Dispatching_Operation (S)
          then