https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89088
--- Comment #1 from Martin Storsjö <martin at martin dot st> --- FWIW, Clang (when operating in MinGW mode, where it tries to follow what GCC does) also had the same issue. There this issue was fixed by making dllexport export inline methods as well, for template instantiations: https://github.com/llvm-project/clang/commit/2061b0cab0002c264af632bf5e6ba5306c589c94
