Fortran: error recovery for invalid CLASS component [PR108434]

gcc/fortran/ChangeLog:

	PR fortran/108434
	* expr.cc (class_allocatable): Prevent NULL pointer dereference
	or invalid read.
	(class_pointer): Likewise.

gcc/testsuite/ChangeLog:

	PR fortran/108434
	* gfortran.dg/pr108434.f90: New test.

Author: harald-anlauf

gcc/fortran/expr.cc

@@ -4996,14 +4996,14 @@ get_union_initializer (gfc_symbol *union_type, gfc_component **map_p)
 static bool
 class_allocatable (gfc_component *comp)
 {
-  return comp->ts.type == BT_CLASS && CLASS_DATA (comp)
+  return comp->ts.type == BT_CLASS && comp->attr.class_ok && CLASS_DATA (comp)
     && CLASS_DATA (comp)->attr.allocatable;
 }
 
 static bool
 class_pointer (gfc_component *comp)
 {
-  return comp->ts.type == BT_CLASS && CLASS_DATA (comp)
+  return comp->ts.type == BT_CLASS && comp->attr.class_ok && CLASS_DATA (comp)
     && CLASS_DATA (comp)->attr.pointer;
 }
 

gcc/testsuite/gfortran.dg/pr108434.f90

@@ -0,0 +1,11 @@
+! { dg-do compile }
+! PR fortran/108434 - ICE in class_allocatable
+! Contributed by G.Steinmetz
+
+program p
+  type t
+     class(c), pointer :: a(2) ! { dg-error "must have a deferred shape" }
+  end type t
+  class(t), allocatable :: x
+  class(t), pointer     :: y
+end