c++: array cv-quals and template specialization [PR101402]
PRs 101402, 102033, etc. demonstrated that the fix for PR92010 wasn't
handling all cases of the CWG1001/1322 issue with parameter type qual
stripping and arrays with templates. The problem turned out to be in
determine_specialization, which did an extra substitution without the 92010
fix and then complained that the result didn't match.
But just removing that wrong/redundant code meant that we were accepting
specializations with different numbers of parameters, because the code in
fn_type_unification that compares types in this case wasn't checking for
length mismatch.
After fixing that, I realized that fn_type_unification couldn't tell the
difference between variadic and non-variadic function types, because the
args array doesn't include the terminal void we use to indicate non-variadic
function type. So I added it, and made the necessary adjustments.
Thanks to qingzhe "nick" huang <nickhuang99@hotmail.com> for the patch that
led me to dig more into this, and the extensive testcases.
* g++.dg/template/fnspec2.C: New test.
* g++.dg/template/parm-cv1.C: New test.
* g++.dg/template/parm-cv2.C: New test.
* g++.dg/template/parm-cv3.C: New test.