[Bug c++/65638] Crash on invalid input

[JamesMikeDuPont at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65638

--- Comment #3 from James Michael DuPont <JamesMikeDuPont at googlemail dot 
com> ---
This test case can be reduced to just a file with the word bool in it.

```
bool
```