[Patch, fortran] PR78474 - gfortran accepts invalid submodule syntax

[Paul Richard Thomas]

Dear All,

This is a rather trivial problem with a similarly trivial fix. The
ChangeLog says it all.

Before anybody asks, the testcase number jumps by two because I am
going through the submodule PRs in reverse order.

Bootstraps and regtests on FC21/x86_64 - OK for trunk and 6-branch?

Paul

2016-11-27  Paul Thomas  <pa...@gcc.gnu.org>

    PR fortran/78474
    * module.c (gfc_match_submodule): If there is more than one
    colon, it is a syntax error.

2016-11-27  Paul Thomas  <pa...@gcc.gnu.org>

    PR fortran/78474
    * gfortran.dg/submodule_22.f08: New test.

Index: gcc/fortran/module.c
===================================================================
*** gcc/fortran/module.c        (revision 242874)
--- gcc/fortran/module.c        (working copy)
*************** gfc_match_submodule (void)
*** 740,745 ****
--- 740,746 ----
    match m;
    char name[GFC_MAX_SYMBOL_LEN + 1];
    gfc_use_list *use_list;
+   bool seen_colon = false;
  
    if (!gfc_notify_std (GFC_STD_F2008, "SUBMODULE declaration at %C"))
      return MATCH_ERROR;
*************** gfc_match_submodule (void)
*** 772,778 ****
        }
        else
        {
!       module_list = use_list;
          use_list->module_name = gfc_get_string (name);
          use_list->submodule_name = use_list->module_name;
        }
--- 773,779 ----
        }
        else
        {
!         module_list = use_list;
          use_list->module_name = gfc_get_string (name);
          use_list->submodule_name = use_list->module_name;
        }
*************** gfc_match_submodule (void)
*** 780,787 ****
        if (gfc_match_char (')') == MATCH_YES)
        break;
  
!       if (gfc_match_char (':') != MATCH_YES)
        goto syntax;
      }
  
    m = gfc_match (" %s%t", &gfc_new_block);
--- 781,791 ----
        if (gfc_match_char (')') == MATCH_YES)
        break;
  
!       if (gfc_match_char (':') != MATCH_YES
!         || seen_colon)
        goto syntax;
+ 
+       seen_colon = true;
      }
  
    m = gfc_match (" %s%t", &gfc_new_block);
Index: gcc/testsuite/gfortran.dg/submodule_22.f08
===================================================================
*** gcc/testsuite/gfortran.dg/submodule_22.f08  (revision 0)
--- gcc/testsuite/gfortran.dg/submodule_22.f08  (working copy)
***************
*** 0 ****
--- 1,47 ----
+ ! { dg-do compile }
+ !
+ ! Test the fix for PR78474.
+ !
+ ! Contributed by Nicholas Brearly  <nick.brea...@cobham.com>
+ !
+ module mtop
+   implicit none
+   real :: r
+   interface
+     module subroutine sub1()
+     end subroutine
+   end interface
+   interface
+     module subroutine sub2()
+     end subroutine
+   end interface
+   interface
+     module subroutine sub3()
+     end subroutine
+   end interface
+ end module mtop
+ 
+ submodule (mtop) submod
+   implicit none
+   real :: s
+ contains
+   module subroutine sub1
+     r = 0.0
+   end subroutine sub1
+ end
+ 
+ submodule (mtop:submod) subsubmod
+ contains
+   module subroutine sub2
+     r = 1.0
+     s = 1.0
+   end subroutine sub2
+ end
+ 
+ submodule (mtop:submod:subsubmod) subsubsubmod ! { dg-error "Syntax error in 
SUBMODULE statement" }
+ contains
+   module subroutine sub3
+     r = 2.0
+     s = 2.0
+   end subroutine sub3
+ end