c++: Distinguish ambiguity from no valid candidate
authorJason Merrill <jason@redhat.com>
Mon, 7 Dec 2020 22:21:47 +0000 (17:21 -0500)
committerJason Merrill <jason@redhat.com>
Tue, 8 Dec 2020 20:11:46 +0000 (15:11 -0500)
commita988a398d6daef3072cd2d07a21980911d8f93fc
tree1bea0109feb54d7acc3e67c0630da2d2e4dcca03
parent447f99b3b8baabbfb33b29123113637e54c5e652
c++: Distinguish ambiguity from no valid candidate

Several recent C++ features are specified to try overload resolution, and if
no viable candidate is found, do something else.  But our error return
doesn't distinguish between that situation and finding multiple viable
candidates that end up being ambiguous.  We're already trying to separately
return the single function we found even if it ends up being ill-formed for
some reason; for ambiguity let's pass back error_mark_node, to be
distinguished from NULL_TREE meaning no viable candidate.

gcc/cp/ChangeLog:

* call.c (build_new_op_1): Set *overload for ambiguity.
(build_new_method_call_1): Likewise.
gcc/cp/call.c