incomplete type for std::any when GMOCKing interface

Question

I have a very weird compilation problem with this snippet:

#include 
#include 


struct Class
{
    virtual std::any get(int, int         


        

Answer 1

This is libstdc++ bug 90415.

I am not sure what it is about std::any that causes this problem. Note that your example fails on clang using libstdc++, but succeeds when using libc++.

Answer 2

Additional information about this issue, that I have got a workaround to use any with gmock in gcc 9.1.0, use std::experimental::fundamentals_v1::any instead of std::any, and it works fine.