[Bug c++/42356] improve list of candidates and error recovery for ambiguous call

["redi at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42356

--- Comment #18 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-10-23 02:03:41 UTC ---
(In reply to comment #12)
> Manual said:
> g++ could also specify which ones are viable candidates, and which ones are not
> even viable, and for the ones not viable, explain why.

None of the functions are viable, because 'newNode' is ambiguous.


So your suggestion seems to be:

request for member is ambiguous
Overload 1: not viable, reason: ambiguous.
Overload 2: not viable, reason: ambiguous.
Overload 3: not viable, reason: ambiguous.
Overload 4: not viable, reason: ambiguous.
Overload 5: not viable, reason: ambiguous.
Overload 6: not viable, reason: ambiguous.

rather than what we have now:

request for member is ambiguous
Overload 1
Overload 2
Overload 3
Overload 4
Overload 5
Overload 6
[unhelpful nonsense about expected primary expression]

I think the second one is better (apart from the primary expression part)

Or maybe you could have:

request for member is ambiguous
Overload 1: not viable, reason: ambiguous.
Overload 2: not viable, reason: ambiguous.
Overload 3: not viable, reason: ambiguous, and wrong number of args
Overload 4: not viable, reason: ambiguous, and wrong number of args
Overload 5: not viable, reason: ambiguous, and wrong number of args
Overload 6: not viable, reason: ambiguous, and wrong number of args

I don't think that helps - changing the number of arguments wouldn't make the
testcase compile. Resolving the ambiguous lookup would.