[Bug fortran/51945] New: Diagnose wrong default initialization of DTs in a DT declaration

[Bug fortran/51945] New: Diagnose wrong default initialization of DTs in a DT declaration

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

             Bug #: 51945
           Summary: Diagnose wrong default initialization of DTs in a DT
                    declaration
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: accepts-invalid, diagnostic
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org


The following program compiles without any error, until one uncomments the
type-declaration line. If one does, one gets the expected error.

Expected: One already gets an error without using the declared type.

The current error is most confusing if one has the type decalaration in a
module as one then gets:

use m
    1
Error: Can't convert TYPE(t3) to TYPE(t) at (1)


type t
integer :: i = 3
end type t

type, extends(t) ::  t2
end type t2

type ::  t3
integer :: i = 78
end type t3

type my_t
  type(t) :: x = t() ! OK
  type(t) :: y = t2() ! Invalid
  type(t) :: z = t3() ! Invalid
end type my_t

!type(my_t) :: a
end

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-08-08
     Ever confirmed|0                           |1

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Between revisions 194897 (2013-01-04: no error) and 195140 (2013-01-14),
gfortran has started to emit the following error for the original test:

pr51945.f90:14.16:

  type(t) :: y = t2() ! Invalid
                1
Error: Can't convert TYPE(t2) to TYPE(t) at (1)

If the type-declaration line 'type(my_t) :: a' is uncommented, the errors
appear once for r194897, but twice for r195140.

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |janus at gcc dot gnu.org

--- Comment #2 from janus at gcc dot gnu.org ---
With current trunk as well as 4.8, the test case with comment gives me:

Error: Can't convert TYPE(t2) to TYPE(t) at (1)

(but not the corresponding error with 't3'). When uncommenting the line I get:

Error: Can't convert TYPE(t2) to TYPE(t) at (1)
Error: Can't convert TYPE(t2) to TYPE(t) at (1)
Error: Can't convert TYPE(t2) to TYPE(t) at (1)
Error: Can't convert TYPE(t3) to TYPE(t) at (1)

(i.e. three times the error about t2 and once about t3).


I guess the expected result would be to get each error once!

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

--- Comment #3 from janus at gcc dot gnu.org ---
Applying the patches from PR 49213 (comments 8, 10 and 16), I get the
following:


1) test case with comment: same as before (error with t2)


2) test case with uncommented line:

c0.f90:15.16:

  type(t) :: y = t2() ! Invalid
                1
Error: Can't convert TYPE(t2) to TYPE(t) at (1)
c0.f90:2.6:

type t
      1
Internal Error at (1):
c0.f90:15.16:

  type(t) :: y = t2() ! Invalid
                1
Can't convert TYPE(t2) to TYPE(t) at (1)


As noted by Dominique, this seems to be due to PR 49213 comment 16, in
particular.

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

--- Comment #4 from janus at gcc dot gnu.org ---
The following patch should somewhat improve the situation:


Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c    (revision 201576)
+++ gcc/fortran/resolve.c    (working copy)
@@ -1178,7 +1178,7 @@ resolve_structure_cons (gfc_expr *expr, int init)
              gfc_basic_typename (comp->ts.type));
           t = false;
         }
-      else
+      else if (!init)
         {
           bool t2 = gfc_convert_type (cons->expr, &comp->ts, 1);
           if (t)
@@ -12344,7 +12344,7 @@ resolve_fl_derived0 (gfc_symbol *sym)

       if (c->initializer && !sym->attr.vtype
       && !gfc_check_assign_symbol (sym, c, c->initializer))
-    return false;
+    continue;
     }

   check_defined_assignments (sym);



The first hunk suppresses the errors in the resolution of the symbol 'a', since
they should already be thrown in the resolution of the type.

The second hunk makes sure one gets the error in both components when resolving
the type (a similar thing is also done in PR 58023 comment 5).


With the above patch I get the expected result on the original test case in
comment 0:

Error: Can't convert TYPE(t2) to TYPE(t) at (1)
Error: Can't convert TYPE(t3) to TYPE(t) at (1)

On the version with the uncommented line, each error unfortunately still
appears twice, but that is due to the fact that the type symbol is resolved
twice (cf. also PR 44978).

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |janus at gcc dot gnu.org

--- Comment #5 from janus at gcc dot gnu.org ---
(In reply to janus from comment #4)
> The following patch should somewhat improve the situation:

... and regtests cleanly.

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

--- Comment #6 from janus at gcc dot gnu.org ---
Btw, here is a variant which triggers an internal error similar to comment 3,
but already with a clean trunk:


type t
integer :: i = 3
end type t

type my_t
  integer :: i = t()
end type

type(my_t) :: a
end

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

--- Comment #7 from janus at gcc dot gnu.org ---
(In reply to janus from comment #6)
> Btw, here is a variant which triggers an internal error similar to comment
> 3, but already with a clean trunk:

I guess one could just get rid of the internal error like this:


Index: gcc/fortran/intrinsic.c
===================================================================
--- gcc/fortran/intrinsic.c    (revision 201631)
+++ gcc/fortran/intrinsic.c    (working copy)
@@ -4430,7 +4430,7 @@ gfc_convert_type (gfc_expr *expr, gfc_typespec *ts
    The possible values are:

      1 Generate a gfc_error()
-     2 Generate a gfc_internal_error().
+     2 No error.

    'wflag' controls the warning related to conversion.  */

@@ -4574,27 +4574,16 @@ gfc_convert_type_warn (gfc_expr *expr, gfc_typespe

   if (gfc_is_constant_expr (expr->value.function.actual->expr)
       && !do_simplify (sym, expr))
-    {
+    return false;        /* Error already generated in do_simplify() */

-      if (eflag == 2)
-    goto bad;
-      return false;        /* Error already generated in do_simplify() */
-    }
-
   return true;

 bad:
   if (eflag == 1)
-    {
-      gfc_error ("Can't convert %s to %s at %L",
-         gfc_typename (&from_ts), gfc_typename (ts), &expr->where);
-      return false;
-    }
+    gfc_error ("Can't convert %s to %s at %L",
+           gfc_typename (&from_ts), gfc_typename (ts), &expr->where);

-  gfc_internal_error ("Can't convert %s to %s at %L",
-              gfc_typename (&from_ts), gfc_typename (ts),
-              &expr->where);
-  /* Not reached */
+  return false;
 }

[Bug fortran/51945] Diagnose wrong default initialization of DTs in a DT declaration

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51945

--- Comment #8 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
I have the patches in comments 4 and 7 for several months. They fix the issues
without regression. Would it helps if I do the packaging?