https://gist.github.com/jpf91/4738922
/tmp/cc8D6NeD.o:(.rodata._D6nested10__T5f7965Z5f7965FNaNbNfZC6nested10__T5f7965Z5f79656Result6Result6__vtblZ[_D6nested10__T5f7965Z5f7965FNaNbNfZC6nested10__T5f7965Z5f79656Result6Result6__vtblZ]+0x30): undefined reference to `_D6nested10__T5f7965Z5f7965FNaNbNfZC6nested10__T5f7965Z5f79656Result6Result1gMFZv' This is currently not detected as needing a closure, it tries to use the gcc nested function mechanism. I guess the gcc mechanism can't handle function->class->function chains as it was developed for c nested functions which can only be nested in functions AFAIK. Background info: We don't call cgraph_finalize_function for GCC nested functions (ObjectFile::outputFunction). This is correct, as cgraph_finalize_function is called by the GCC middle / backend. But I think in this case we're passing something to the backend which it can't handle. Therefore cgraph_finalize_function is never called and the function is not put out. Uncommenting the /*a = 42;*/ makes everything work as we use the D closure code path in that case. Marking the Result class as static also works. Do you know how we could force the D closure codepath in such cases or how we should solve this? (I actually found a fix for that verify_callgraph problem. But it triggered some regressions which are actually caused by this bug.)
