PR fortran/95587 - ICE in gfc_target_encode_expr, at fortran/target-memory.c:362

EQUIVALENCE objects are subject to constraints listed in the Fortran 2018
standard, section 8.10.1.1.  These constraints are to be checked
also for CLASS variables.

gcc/fortran/
	PR fortran/95587
	* match.c (gfc_match_equivalence): Check constraints on
	EQUIVALENCE objects also for CLASS variables.

(cherry picked from commit 5eb947601bdce59f2ff26694327ad173c51c2724)

gcc/fortran/match.c

@@ -5700,6 +5700,11 @@ gfc_match_equivalence (void)
 
 	  if (!gfc_add_in_equivalence (&sym->attr, sym->name, NULL))
 	    goto cleanup;
+	  if (sym->ts.type == BT_CLASS
+	      && CLASS_DATA (sym)
+	      && !gfc_add_in_equivalence (&CLASS_DATA (sym)->attr,
+					  sym->name, NULL))
+	    goto cleanup;
 
 	  if (sym->attr.in_common)
 	    {

gcc/testsuite/gfortran.dg/pr95587.f90

+! { dg-do compile }
+! PR fortran/95587 - ICE in gfc_target_encode_expr, at fortran/target-memory.c:362
+
+program p
+  type t
+  end type t
+  class(*), allocatable :: x, y
+  class(t), allocatable :: u, v
+  class(t),    pointer  :: c, d
+  equivalence (x, y) ! { dg-error "conflicts with ALLOCATABLE" }
+  equivalence (u, v) ! { dg-error "conflicts with ALLOCATABLE" }
+  equivalence (c, d) ! { dg-error "conflicts with POINTER" }
+end