https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98231
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:796ead19f85372e59217c9888db688a2fe11b54f commit r11-6652-g796ead19f85372e59217c9888db688a2fe11b54f Author: Marek Polacek <pola...@redhat.com> Date: Wed Jan 13 11:09:14 2021 -0500 c++: Failure to lookup using-decl name [PR98231] In r11-4690 we removed the call to finish_nonmember_using_decl in tsubst_expr/DECL_EXPR in the USING_DECL block. This was done not to perform name lookup twice for a non-dependent using-decl, which sounds sensible. However, finish_nonmember_using_decl also pushes the decl's bindings which we still have to do so that we can find the USING_DECL's name later. In this case, we've got a USING_DECL N::operator<< that we are tsubstituting. We already looked it up while parsing the template "foo", and lookup_using_decl stashed the OVERLOAD it found into USING_DECL_DECLS. Now we just have to update the IDENTIFIER_BINDING of the identifier for operator<< with the overload the name is bound to. I didn't want to export push_local_binding so I've introduced a new wrapper. gcc/cp/ChangeLog: PR c++/98231 * name-lookup.c (push_using_decl_bindings): New. * name-lookup.h (push_using_decl_bindings): Declare. * pt.c (tsubst_expr): Call push_using_decl_bindings. gcc/testsuite/ChangeLog: PR c++/98231 * g++.dg/lookup/using63.C: New test.