[Bug c++/86307] New: Function template and ?: causes segfault

["zhonghao at pku dot org.cn" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86307

            Bug ID: 86307
           Summary: Function template and ?: causes segfault
           Product: gcc
           Version: 8.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhonghao at pku dot org.cn
  Target Milestone: ---

The code is as follow:

template<class X> void ook();
typedef int (*tf)();
typedef void (*ookf)();
tf r1;
ookf r2, r3;
bool r4, r5;
bool c1;
ookf c2, c3;
void a() {
 // rejected
 r1 = reinterpret_cast<tf>(ook<int>);
 r2 = 1 ? ook<int> : 0;
 r3 = *ook<int>;
 r4 = 1 || ook<int>;
 r5 = ook<int> == ook<int>;

 // crash in codegen
 c1 = !ook<int>;

 // crash in sema
 c2 = 1 ? ook<int> : ook<int>;
 c3 = (0, ook<int>);
}

clang++ accepts it, but g++ rejects it:

code2.c.cpp:14:12: error: invalid operands of types '<unresolved overloaded
function type>' and 'int' to binary 'operator!='
  r4 = 1 || ook<int>;
            ^~~~~~~~
code2.c.cpp:15:16: error: invalid operands of types '<unresolved overloaded
function type>' and '<unresolved overloaded function type>' to binary
'operator=='
  r5 = ook<int> == ook<int>;
       ~~~~~~~~~^~~~~~~~~~~
code2.c.cpp:22:11: error: no context to resolve type of 'ook<int>'
  c3 = (0, ook<int>);
           ^~~~~~~~

The code comes from a clang bug
report:https://bugs.llvm.org/show_bug.cgi?id=7863

 Eli Friedman  believes that it is valid.