https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100335
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to W E Brown from comment #4) > In brief, I believe Comment 3's example ought compile due to > [namespace.udecl]/14, but the original example ought not compile due to > [over.load]/2.3. But [over.load]/2.3 is not why GCC gives an error. The definition of Derived is accepted, it's trying to call declval<const Derived&>().method() that is rejected. None of GCC, Clang, EDG or MSVC reject the definition of Derived. (In reply to Daniel from comment #5) > As a sidenote, the original example is also compiling if test object is made > non-const, i.e. "const Derived test;" is replaced with "Derived test;" > > If the argument in Comment 1 is true than the program would still be > ill-formed in this case, wouldn't it? Yes. I'm not sure what the relevant rule is here, but I don't think it's [over.load]/2.3
