https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99901
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:8685348075d91945066dea9b564bd42cbc1d22bd commit r11-8017-g8685348075d91945066dea9b564bd42cbc1d22bd Author: Jason Merrill <ja...@redhat.com> Date: Tue Apr 6 01:21:05 2021 -0400 c++: C++17 constexpr static data member linkage [PR99901] C++17 makes constexpr static data members implicitly inline variables. In C++14, a subsequent out-of-class declaration is the definition. We want to continue emitting a symbol for such a declaration in C++17 mode, for ABI compatibility with C++14 code that wants to refer to it. Normally I'd distinguish in- and out-of-class declarations by looking at DECL_IN_AGGR_P, but we never set DECL_IN_AGGR_P on inline variables. I think that's wrong, but don't want to mess with it so close to release. Conveniently, we already have a test for in-class declaration earlier in the function. gcc/cp/ChangeLog: PR c++/99901 * decl.c (cp_finish_decl): mark_needed an implicitly inline static data member with an out-of-class redeclaration. gcc/testsuite/ChangeLog: PR c++/99901 * g++.dg/cpp1z/inline-var9.C: New test.
