https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110358
--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:c7607c4cf18986025430ca8626abfe56bfe87106 commit r14-9263-gc7607c4cf18986025430ca8626abfe56bfe87106 Author: Marek Polacek <pola...@redhat.com> Date: Thu Jan 25 16:38:51 2024 -0500 c++: implement [[gnu::no_dangling]] [PR110358] Since -Wdangling-reference has false positives that can't be prevented, we should offer an easy way to suppress the warning. Currently, that is only possible by using a #pragma, either around the enclosing class or around the call site. But #pragma GCC diagnostic tend to be onerous. A better solution would be to have an attribute. To that end, this patch adds a new attribute, [[gnu::no_dangling]]. This attribute takes an optional bool argument to support cases like: template <typename T> struct [[gnu::no_dangling(std::is_reference_v<T>)]] S { // ... }; PR c++/110358 PR c++/109642 gcc/cp/ChangeLog: * call.cc (no_dangling_p): New. (reference_like_class_p): Use it. (do_warn_dangling_reference): Use it. Don't warn when the function or its enclosing class has attribute gnu::no_dangling. * tree.cc (cxx_gnu_attributes): Add gnu::no_dangling. (handle_no_dangling_attribute): New. gcc/ChangeLog: * doc/extend.texi: Document gnu::no_dangling. * doc/invoke.texi: Mention that gnu::no_dangling disables -Wdangling-reference. gcc/testsuite/ChangeLog: * g++.dg/ext/attr-no-dangling1.C: New test. * g++.dg/ext/attr-no-dangling2.C: New test. * g++.dg/ext/attr-no-dangling3.C: New test. * g++.dg/ext/attr-no-dangling4.C: New test. * g++.dg/ext/attr-no-dangling5.C: New test. * g++.dg/ext/attr-no-dangling6.C: New test. * g++.dg/ext/attr-no-dangling7.C: New test. * g++.dg/ext/attr-no-dangling8.C: New test. * g++.dg/ext/attr-no-dangling9.C: New test.
