I wrote:
Committed as r274551.
Well, this revision appears to have woken quite a few bugs from their slumber. While argument mismatch was always illegal, it seems to have been a common idiom at one time. And, like almost all bad habits of the past, SPEC also has this (see PR 91473, where you can see thatt a rather large number of SPEC tests now require -std=legacy). So, what to do? Is -std=legacy the right option, or should we add something different (like -faccept-argument-mismatch), which we could then set by -std=legacy? And is there anything special we should be doing after we have diagnoses the problem, if the user simply wants to run the code?