PR fortran/28081

	* resolve.c (resolve_substring): Don't issue out-of-bounds
	error messages when the range has zero size.

	* gfortran.dg/substr_3.f: New test.
	* gfortran.dg/equiv_2.f90: Update expected error message.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@114972 138bc75d-0d04-0410-961f-82ee72b054a4