https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52321
--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Ivan Godard from comment #4) > Define an enum of reasons with "success" first, flop the sense of the test > so that false means coercion was OK (grep to find all calls and put a "!" in > front of each), and return the reason enum instead of bool. The code that is > reason-aware saves the enum and builds a good message; the legacy code that > is not reason-aware treats the enum as a bool and works as before except for > the inverted sense of the test. Maybe half an hour of work. A much simpler "good enough" solution is to just leave build_static_cast_1 alone. In the caller, if the cast fails and one or both types is a pointer/reference to incomplete class, issue a note. It doesn't matter if the reason it failed is the incomplete type, because I don't try to say that, I just say it's incomplete.
