[Bug c++/106179] New: [13 Regression] Rejected code since r13-1390-g07ac550393d00fca

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106179

            Bug ID: 106179
           Summary: [13 Regression] Rejected code since
                    r13-1390-g07ac550393d00fca
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: jason at gcc dot gnu.org, slyfox at gcc dot gnu.org
  Target Milestone: ---

The following is rejected:

$ cat algo.ii
struct Mat {
  template <typename> Mat();
};
template <typename> struct Mat_;
template <typename _Tp> Mat::Mat() {
  _Tp commaInitializer = commaInitializer.operator Mat_<_Tp>;
}

$ g++ algo.ii -c
algo.ii: In constructor ‘Mat::Mat()’:
algo.ii:6:52: error: invalid template-id
    6 |   _Tp commaInitializer = commaInitializer.operator Mat_<_Tp>;
      |                                                    ^~~~