[Bug c++/65970] New: [C++14] Endless loop with constexpr

["reichelt at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65970

            Bug ID: 65970
           Summary: [C++14] Endless loop with constexpr
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: reichelt at gcc dot gnu.org
  Target Milestone: ---

The compiler loops forever when compiling the following invalid testcase with
-std=c++14:

========================
constexpr int foo()
{
  while (true) x;
  return 0;
}

int i = foo();
========================

At least it gives an error before it hangs:

bug.cc: In function 'constexpr int foo()':
bug.cc:3:16: error: 'x' was not declared in this scope
   while (true) x;