https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61412
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Matt Godbolt from comment #0) > --begin example > # 88 "some/file.cpp" 3 4 > struct Foo { int i, j; Foo() : j(1), i(0) {} }; > --end example How did you produce that file? If you compile the exact preprocessor output you shouldn't have a problem. If you mangle it, fooling the compiler into thinking it's in a system header, you have a problem.