[Fortran] ICE: Invalid expression in gfc_element_size PR93601

ICE occurs when assigning a BOZ constant to an class(*) variable
with the allocatable attribute. Use of BOZ constants outside
data statements and int/real/dble/cmplx intrinsics is not allowed.

Original patch provided by Steven G. Kargl  <kargl@gcc.gnu.org>.

gcc/fortran/ChangeLog

	PR fortran/93601
	* match.c (gfc_match_assignment) : Reject assignment if
	the lhs stype is BT_CLASS and the rhs type is BT_BOZ.

gcc/testsuite/ChangeLog

	PR fortran/93601
	* gfortran.dg/pr93601.f90 : New test.

gcc/fortran/ChangeLog

 2020-02-18  Steven G. Kargl  <kargl@gcc.gnu.org>
 
+	PR fortran/93601
+	* match.c (gfc_match_assignment) : Reject assignment if
+	the lhs stype is BT_CLASS and the rhs type is BT_BOZ.
+
+2020-02-18  Steven G. Kargl  <kargl@gcc.gnu.org>
+
 	PR fortran/93603
 	* match.c (gfc_match_associate) : If target expression
 	has the type BT_BOZ output an error and goto

gcc/fortran/match.c

@@ -1348,6 +1348,16 @@ gfc_match_assignment (void)
   rvalue = NULL;
   m = gfc_match (" %e%t", &rvalue);
 
+  if (m == MATCH_YES
+      && rvalue->ts.type == BT_BOZ
+      && lvalue->ts.type == BT_CLASS)
+    {
+      m = MATCH_ERROR;
+      gfc_error ("BOZ literal constant at %L is neither a DATA statement "
+		 "value nor an actual argument of INT/REAL/DBLE/CMPLX "
+		 "intrinsic subprogram", &rvalue->where);
+    }
+
   if (lvalue->expr_type == EXPR_CONSTANT)
     {
       /* This clobbers %len and %kind.  */

gcc/testsuite/ChangeLog

+2020-02-18  Mark Eggleston  <mark.eggleston@codethink.com>
+
+	PR fortran/93601
+	* gfortran.dg/pr93601.f90 : New test.
+
 2020-02-18  Martin Liska  <mliska@suse.cz>
 
 	PR ipa/93583

gcc/testsuite/gfortran.dg/pr93601.f90

+! { dg-do compile }
+
+program p
+   class(*), allocatable :: z
+   z = z'1' ! { dg-error "BOZ literal constant at" }
+end
+