https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109918
--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Simon Martin <simar...@gcc.gnu.org>: https://gcc.gnu.org/g:60163c85730e6b7c566e219222403ac87ddbbddd commit r15-4282-g60163c85730e6b7c566e219222403ac87ddbbddd Author: Simon Martin <si...@nasilyan.com> Date: Fri Oct 11 10:16:26 2024 +0200 c++: Fix overeager Woverloaded-virtual with conversion operators [PR109918] We currently emit an incorrect -Woverloaded-virtual warning upon the following test case === cut here === struct A { virtual operator int() { return 42; } virtual operator char() = 0; }; struct B : public A { operator char() { return 'A'; } }; === cut here === The problem is that when iterating over ovl_range (fns), warn_hidden gets confused by the conversion operator marker, concludes that seen_non_override is true and therefore emits a warning for all conversion operators in A that do not convert to char, even if -Woverloaded-virtual is 1 (e.g. with -Wall, the case reported). A second set of problems is highlighted when -Woverloaded-virtual is 2. First, with the same test case, since base_fndecls contains all conversion operators in A (except the one to char, that's been removed when iterating over ovl_range (fns)), we emit a spurious warning for the conversion operator to int, even though it's unrelated. Second, in case there are several conversion operators with different cv-qualifiers to the same type in A, we rightfully emit a warning, however the note uses the location of the conversion operator marker instead of the right one; location_of should go over conv_op_marker. This patch fixes all these by explicitly keeping track of (1) base methods that are overriden, as well as (2) base methods that are hidden but not overriden (and by what), and warning about methods that are in (2) but not (1). It also ignores non virtual base methods, per "definition" of -Woverloaded-virtual. PR c++/109918 gcc/cp/ChangeLog: * class.cc (warn_hidden): Keep track of overloaded and of hidden base methods. Mention the actual hiding function in the warning, not the first overload. * error.cc (location_of): Skip over conv_op_marker. gcc/testsuite/ChangeLog: * g++.dg/warn/Woverloaded-virt1.C: Check that no warning is emitted for non virtual base methods. * g++.dg/warn/Woverloaded-virt5.C: New test. * g++.dg/warn/Woverloaded-virt6.C: New test. * g++.dg/warn/Woverloaded-virt7.C: New test. * g++.dg/warn/Woverloaded-virt8.C: New test. * g++.dg/warn/Woverloaded-virt9.C: New test.
