[Bug fortran/123903] Usage of unallocated `character` variable in `//` does not trigger warning

[anlauf at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123903

--- Comment #3 from anlauf at gcc dot gnu.org ---
(In reply to anlauf from comment #1)
> We should be able to make one of the -fcheck=... options handle this.

Actuall all unary and binary operations are affected.  Example:

  integer, allocatable :: i, k
  i = -i
  k = k + 24
  print *, i, k
end

This seems to run fine, but valgrind says it should not.