[gcc r13-4605] Fortran: fix ICE on bad use of statement function [PR107995]

[Harald Anlauf <anlauf@gcc.gnu.org>]

https://gcc.gnu.org/g:8f72249ff4cbd0a5c701b99ee8aa1ca9d82df046

commit r13-4605-g8f72249ff4cbd0a5c701b99ee8aa1ca9d82df046
Author: Steve Kargl <kargl@gcc.gnu.org>
Date:   Sat Dec 10 22:17:15 2022 +0100

    Fortran: fix ICE on bad use of statement function [PR107995]
    
    gcc/fortran/ChangeLog:
    
            PR fortran/107995
            * interface.cc (gfc_check_dummy_characteristics): Reject statement
            function dummy arguments.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/107995
            * gfortran.dg/pr107995.f90: New test.

Diff:
---
 gcc/fortran/interface.cc               |  6 ++++++
 gcc/testsuite/gfortran.dg/pr107995.f90 | 10 ++++++++++
 2 files changed, 16 insertions(+)

diff --git a/gcc/fortran/interface.cc b/gcc/fortran/interface.cc
index 73799c175b7..7d8eeda5a99 100644
--- a/gcc/fortran/interface.cc
+++ b/gcc/fortran/interface.cc
@@ -1334,6 +1334,12 @@ gfc_check_dummy_characteristics (gfc_symbol *s1, gfc_symbol *s2,
   if (s1 == NULL || s2 == NULL)
     return s1 == s2 ? true : false;
 
+  if (s1->attr.proc == PROC_ST_FUNCTION || s2->attr.proc == PROC_ST_FUNCTION)
+    {
+      strncpy (errmsg, "Statement function", err_len);
+      return false;
+    }
+
   /* Check type and rank.  */
   if (type_must_agree)
     {
diff --git a/gcc/testsuite/gfortran.dg/pr107995.f90 b/gcc/testsuite/gfortran.dg/pr107995.f90
new file mode 100644
index 00000000000..22e878630b8
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr107995.f90
@@ -0,0 +1,10 @@
+! { dg-do compile }
+! PR fortran/107995
+! Contributed by G.Steinmetz
+
+program p
+  implicit none
+  integer :: n  ! { dg-error "Self-referential argument" }
+  n(n) = 1      ! { dg-warning "Statement function" }
+  print *, n(n) ! { dg-error "Statement function" }
+end