https://gcc.gnu.org/bugzilla/show_bug.cgi?id=13166
Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |msebor at gcc dot gnu.org Known to fail| |3.3, 4.5.3, 4.8.3, 4.9.3, | |5.3.0, 6.3.0, 7.0 --- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> --- GCc 7.0 still accepts the small test case from comment #2. Clang rejects it with: t.C:4:13: error: friend declaration specifying a default argument must be a definition friend int compare_unsigned(int if_v_signed = 0); ^ 1 error generated.