[Patch, fortran] PR fortran/100018 - ICE on missing polymorphic argument

[José Rui Faustino de Sousa via Gcc-patches]

Hi all!

Proposed patch to PR100018 - ICE on missing polymorphic argument.

Patch tested only on x86_64-pc-linux-gnu.

Add association check before de-referencing pointer in order to avoid ICE.

Thank you very much.

Best regards,
José Rui


    2021-4-10  José Rui Faustino de Sousa  <jrfso...@gmail.com>

gcc/fortran/ChangeLog:

        PR fortran/100018
        * resolve.c: Add association check before de-referencing
        pointer.


gcc/testsuite/ChangeLog:

        PR fortran/100018
        * gfortran.dg/PR10018.f90: New test.


diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 1c9b0c5cb62..dd4b26680e0 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -11999,6 +11999,7 @@ start:
 	    /* Assigning a class object always is a regular assign.  */
 	    if (code->expr2->ts.type == BT_CLASS
 		&& code->expr1->ts.type == BT_CLASS
+		&& CLASS_DATA (code->expr2)
 		&& !CLASS_DATA (code->expr2)->attr.dimension
 		&& !(gfc_expr_attr (code->expr1).proc_pointer
 		     && code->expr2->expr_type == EXPR_VARIABLE
diff --git a/gcc/testsuite/gfortran.dg/PR10018.f90 b/gcc/testsuite/gfortran.dg/PR10018.f90
new file mode 100644
index 00000000000..f1cf2676f85
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/PR10018.f90
@@ -0,0 +1,11 @@
+! { dg-do compile }
+!
+subroutine foo(that)
+  implicit none
+  class(*),  target, intent(in)  :: this
+  class(*), pointer, intent(out) :: that
+
+  that => this
+  return
+end subroutine foo
+! { dg-error "Symbol at \\\(1\\\) is not a DUMMY variable" "" { target "*-*-*" } 5 }