From a418129273725fd02e881e6fb5e0877287a1356c Mon Sep 17 00:00:00 2001
From: Steve Kargl <kargl@gcc.gnu.org>
Date: Wed, 15 Feb 2023 22:20:22 +0100
Subject: [PATCH] Fortran: error recovery on invalid assumed size reference
 [PR104554]

gcc/fortran/ChangeLog:

	PR fortran/104554
	* resolve.cc (check_assumed_size_reference): Avoid NULL pointer
	dereference.

gcc/testsuite/ChangeLog:

	PR fortran/104554
	* gfortran.dg/pr104554.f90: New test.
---
 gcc/fortran/resolve.cc                 |  8 +++++---
 gcc/testsuite/gfortran.dg/pr104554.f90 | 11 +++++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr104554.f90

diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc
index 96c34065691..fb0745927ac 100644
--- a/gcc/fortran/resolve.cc
+++ b/gcc/fortran/resolve.cc
@@ -1670,9 +1670,11 @@ check_assumed_size_reference (gfc_symbol *sym, gfc_expr *e)

   /* FIXME: The comparison "e->ref->u.ar.type == AR_FULL" is wrong.
      What should it be?  */
-  if (e->ref && (e->ref->u.ar.end[e->ref->u.ar.as->rank - 1] == NULL)
-	  && (e->ref->u.ar.as->type == AS_ASSUMED_SIZE)
-	       && (e->ref->u.ar.type == AR_FULL))
+  if (e->ref
+      && e->ref->u.ar.as
+      && (e->ref->u.ar.end[e->ref->u.ar.as->rank - 1] == NULL)
+      && (e->ref->u.ar.as->type == AS_ASSUMED_SIZE)
+      && (e->ref->u.ar.type == AR_FULL))
     {
       gfc_error ("The upper bound in the last dimension must "
 		 "appear in the reference to the assumed size "
diff --git a/gcc/testsuite/gfortran.dg/pr104554.f90 b/gcc/testsuite/gfortran.dg/pr104554.f90
new file mode 100644
index 00000000000..099f219c85d
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr104554.f90
@@ -0,0 +1,11 @@
+! { dg-do compile }
+! PR fortran/104554 - ICE in check_assumed_size_reference
+! Contributed by G.Steinmetz
+
+program p
+  type t
+     integer :: a
+  end type
+  class(t) :: x(*) ! { dg-error "Assumed size array" }
+  x%a = 3
+end
--
2.35.3