1.1 --- a/test/maps_test.cc	Thu Feb 25 09:46:12 2021 +0100
     1.2 +++ b/test/maps_test.cc	Tue Jul 28 21:23:36 2020 +0200
     1.3 @@ -61,6 +61,9 @@
     1.4    typedef A argument_type;
     1.5    typedef B result_type;
     1.6  
     1.7 +  F() {};
     1.8 +  F(const F&) {};
     1.9 +
    1.10    B operator()(const A&) const { return B(); }
    1.11  private:
    1.12    F& operator=(const F&);