https://gcc.gnu.org/ml/fortran/2016-08/msg00144.html

On Wed, Aug 24, 2016 at 5:14 PM, Fritz Reese <fritzoreese@gmail.com> wrote:
> With a few recent notes by others, I have identified that the
> comparison logic I used in interface.c (compare_components,
> gfc_compare_derived_types) was faulty in a few ways.
(snip)
> tl;dr: The attached patch fixes PR 77327 and another bug which is
> demonstrated in the included testcase.


Minor correction to a typo in the patch above - should be checking
cmp1 and cmp2 not cmp1 and cmp1:


diff --git a/gcc/fortran/interface.c b/gcc/fortran/interface.c
index ffc36f5..f082464 100644
--- a/gcc/fortran/interface.c
+++ b/gcc/fortran/interface.c
@@ -425,7 +425,7 @@ compare_components (gfc_component *cmp1, gfc_component *cmp2
     gfc_symbol *derived1, gfc_symbol *derived2)
 {
   /* Compare names, but not for anonymous components such as UNION or MAP.  */
-  if (!is_anonymous_component (cmp1) && !is_anonymous_component (cmp1)
+  if (!is_anonymous_component (cmp1) && !is_anonymous_component (cmp2)
       && strcmp (cmp1->name, cmp2->name) != 0)
     return 0;

---
Fritz Reese

2016-08-24  Fritz Reese  <fritzoreese@gmail.com>

        PR fortran/77327
        gcc/fortran/
        * interface.c (is_anonymous_component, is_anonymous_dt): New functions.
        * interface.c (compare_components, gfc_compare_derived_types): Use new
        functions.

        gcc/testsuite/gfortran.dg/
        * dec_structure_13.f90: New testcase.