https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81605
Bug ID: 81605 Summary: -Wignored-attributes emitted when decltype(function) used in template for function with __nonnull__ Product: gcc Version: 7.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: bloerwald at googlemail dot com Target Milestone: --- When using the type of a function with attribute __nonnull__ as a template parameter, -Wignored-attributes is emitted. With other attributes, like __noreturn__, no warning is given. Emitting the warning seems wrong since attributes are not part of a typename and thus can't be handled by e.g. c++17's std::is_invocable. Tested with 6.1.0 (afaik -Wignored-attributes was introduced in 6) and 7.1.0. Not tested with trunk/8. $ cat gcc_ignored_attributes.cpp int fun() __attribute__((ATTRIBUTE)); template<typename> auto templ = 0; auto x = templ<decltype(fun)>; $ gcc/6.1.0/bin/g++ --std=c++14 -c gcc_ignored_attributes.cpp -o/dev/null -DATTRIBUTE=__nonnull__ gcc_ignored_attributes.cpp:4:10: warning: ignoring attributes on template argument ‘int()’ [-Wignored-attributes] auto x = templ<decltype(fun)>; ^~~~~~~~~~~~~~~~~~~~ $ gcc/6.1.0/bin/g++ --std=c++14 -c gcc_ignored_attributes.cpp -o/dev/null -DATTRIBUTE=__noreturn__ $ clang/4.0.1/bin/clang++ --std=c++14 -c gcc_ignored_attributes.cpp -o/dev/null -DATTRIBUTE=__nonnull__ $ clang/4.0.1/bin/clang++ --std=c++14 -c gcc_ignored_attributes.cpp -o/dev/null -DATTRIBUTE=__noreturn__ $