[Bug c++/93785] New: g++ crash/hang on invalid template

[dimhen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93785

            Bug ID: 93785
           Summary: g++ crash/hang on invalid template
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dimhen at gmail dot com
  Target Milestone: ---

r257061 FAIL -- SVN/gcc version 8.0.1 20180125
r10-6659 FAIL

$ cat x.ii
template <typename a, typename = a> struct b {
  struct c;
  b<c> d
} using e = b<int>;
e f;

$ ~/arch-gcc/gcc_current/bin/g++ -fpreprocessed -fchecking=0 -O0 -c x.ii
x.ii:3:8: error: expected ‘;’ at end of member declaration
    3 |   b<c> d
      |        ^
      |         ;
x.ii:4:2: error: expected ‘;’ after struct definition
    4 | } using e = b<int>;
      |  ^
      |  ;
^C

run indefinitely, then killed by OOM-killer.