Index: /svn/trunk/gcc/fortran/resolve.c
===================================================================
*** /svn/trunk/gcc/fortran/resolve.c	(revision 129068)
--- /svn/trunk/gcc/fortran/resolve.c	(working copy)
*************** resolve_actual_arglist (gfc_actual_argli
*** 971,976 ****
--- 971,983 ----
  	  continue;
  	}
  
+       if (e->expr_type == FL_VARIABLE && e->symtree->ambiguous)
+ 	{
+ 	  gfc_error ("'%s' at %L is ambiguous", e->symtree->n.sym->name,
+ 		     &e->where);
+ 	  return FAILURE;
+ 	}
+ 
        if (e->ts.type != BT_PROCEDURE)
  	{
  	  if (gfc_resolve_expr (e) != SUCCESS)
Index: /svn/trunk/gcc/testsuite/gfortran.dg/ambiguous_specific_1.f90
===================================================================
*** /svn/trunk/gcc/testsuite/gfortran.dg/ambiguous_specific_1.f90	(revision 0)
--- /svn/trunk/gcc/testsuite/gfortran.dg/ambiguous_specific_1.f90	(revision 0)
***************
*** 0 ****
--- 1,38 ----
+ ! { dg-do compile }
+ ! Checks the fix for PR33542, in which the ambiguity in the specific
+ ! interfaces of foo was missed.
+ !
+ ! Contributed by Tobias Burnus <burnus@gcc.gnu.org>
+ !
+ MODULE M1
+    INTERFACE FOO
+      MODULE PROCEDURE FOO
+    END INTERFACE
+ CONTAINS
+    SUBROUTINE FOO(I)
+      INTEGER, INTENT(IN) :: I
+      WRITE(*,*) 'INTEGER'
+    END SUBROUTINE FOO
+ END MODULE M1
+ 
+ MODULE M2
+    INTERFACE FOO
+      MODULE PROCEDURE FOO
+    END INTERFACE
+ CONTAINS
+    SUBROUTINE FOO(R)
+      REAL, INTENT(IN) :: R
+      WRITE(*,*) 'REAL'
+    END SUBROUTINE FOO
+ END MODULE M2
+ 
+ PROGRAM P
+    USE M1
+    USE M2
+    implicit none
+    external bar
+    CALL FOO(10)
+    CALL FOO(10.)
+    call bar (foo)  ! { dg-error "is ambiguous" }
+ END PROGRAM P
+ ! { dg-final { cleanup-modules "m1 m2" } }