[Ada] Fix hiding of user-defined operator that is not a homograph
This adds a missing test for the presence of a homograph when applying
the RM 8.4(10) clause about the visibility of operators, and removes
resolution code made obsolete by the change. There is also a fixlet
for a previously undetected ambiguity in the runtime.
gcc/ada/
* sem_res.adb (Resolve_Eqyality_Op): Remove obsolete code.
(Resolve_Op_Not): Likewise.
* sem_type.adb (Disambiguate): Add missing test for RM 8.4(10).
* libgnat/s-dwalin.adb (Enable_Cache): Fix ambiguity.
(Symbolic_Address): Likewise.
gcc/testsuite/
* gnat.dg/equal7.adb: Add expected error messages (code is now
illegal).