Fortran : ICE on invalid code PR95398

Fortran  : ICE on invalid code PR95398

The CLASS_DATA macro is used to shorten the code accessing the derived
components of an expressions type specification.  If the type is not
BT_CLASS the derived pointer is NULL resulting in an ICE.  To avoid
dereferencing a NULL pointer the type should be BT_CLASS.

2020-09-01  Steven G. Kargl  <kargl@gcc.gnu.org>

gcc/fortran

	PR fortran/95398
	* resolve.c (resolve_select_type): Add check for BT_CLASS
	type before using the CLASS_DATA macro which will have a
	NULL pointer to derive components if it isn't BT_CLASS.

2020-09-01  Mark Eggleston  <markeggleston@gcc.gnu.org>

gcc/testsuite

	PR fortran/95398
	* gfortran.dg/pr95398.f90: New test.