[Bug c++/94190] New: [10 Regression] error: no post-decrement operator for type since r10-7096-gd417b4f5414d9076

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94190

            Bug ID: 94190
           Summary: [10 Regression] error: no post-decrement operator for
                    type since r10-7096-gd417b4f5414d9076
           Product: gcc
           Version: 10.0
            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
  Target Milestone: ---

Reduced from boost:extra:

$ cat boost.ii
class {
  typedef long a;
  operator a &();
} b;
template <class> void c() { b--; }

$ g++ boost.ii -c
boost.ii: In function ‘void c()’:
boost.ii:5:30: error: no post-decrement operator for type
    5 | template <class> void c() { b--; }
      |                      

$ g++-9 boost.ii -c