[Bug c++/43064] improve location and text of diagnostics in constructor initializer lists

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43064

--- Comment #9 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Candidate patch:
  https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00304.html