[Patch, Fortran, F03] PR77596: procedure pointer component with implicit interface can point to a function

[Janus Weil]

Hi all,

here is a simple patch for the accepts-invalid problem of PR77596.
Regtests cleanly on x86_64-linux-gnu. Ok for trunk?

Cheers,
Janus


2016-11-08  Janus Weil  <ja...@gcc.gnu.org>

    PR fortran/77596
    * expr.c (gfc_check_pointer_assign): Add special check for procedure-
    pointer component with absent interface.

2016-11-08  Janus Weil  <ja...@gcc.gnu.org>

    PR fortran/77596
    * gfortran.dg/proc_ptr_comp_46.f90: New test.

Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c  (Revision 241956)
+++ gcc/fortran/expr.c  (Arbeitskopie)
@@ -3445,7 +3445,7 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_ex
     {
       char err[200];
       gfc_symbol *s1,*s2;
-      gfc_component *comp;
+      gfc_component *comp1, *comp2;
       const char *name;
 
       attr = gfc_expr_attr (rvalue);
@@ -3549,9 +3549,9 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_ex
            }
        }
 
-      comp = gfc_get_proc_ptr_comp (lvalue);
-      if (comp)
-       s1 = comp->ts.interface;
+      comp1 = gfc_get_proc_ptr_comp (lvalue);
+      if (comp1)
+       s1 = comp1->ts.interface;
       else
        {
          s1 = lvalue->symtree->n.sym;
@@ -3559,18 +3559,18 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_ex
            s1 = s1->ts.interface;
        }
 
-      comp = gfc_get_proc_ptr_comp (rvalue);
-      if (comp)
+      comp2 = gfc_get_proc_ptr_comp (rvalue);
+      if (comp2)
        {
          if (rvalue->expr_type == EXPR_FUNCTION)
            {
-             s2 = comp->ts.interface->result;
+             s2 = comp2->ts.interface->result;
              name = s2->name;
            }
          else
            {
-             s2 = comp->ts.interface;
-             name = comp->name;
+             s2 = comp2->ts.interface;
+             name = comp2->name;
            }
        }
       else if (rvalue->expr_type == EXPR_FUNCTION)
@@ -3591,6 +3591,15 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_ex
       if (s2 && s2->attr.proc_pointer && s2->ts.interface)
        s2 = s2->ts.interface;
 
+      /* Special check for the case of absent interface on the lvalue.
+       * All other interface checks are done below. */
+      if (!s1 && comp1 && comp1->attr.subroutine && s2 && s2->attr.function)
+       {
+         gfc_error ("Interface mismatch in procedure pointer assignment "
+                    "at %L: '%s' is not a subroutine", &rvalue->where, name);
+         return false;
+       }
+
       if (s1 == s2 || !s1 || !s2)
        return true;
 

! { dg-do compile }
!
! PR 77596: [F03] procedure pointer component with implicit interface can point to a function
!
! Contributed by toK <t.kon...@leeds.ac.uk>

program xxx
  implicit none

  type tf
     procedure(), nopass, pointer :: fp
  end type tf

  call ass()

contains

  integer function ff(x)
    integer, intent(in) :: x
    ff = x + 1
  end function ff

  subroutine ass()
    type(tf) :: p
    p%fp=>ff        ! { dg-error "is not a subroutine" }
    call p%fp(3)
  end subroutine ass

end