[Bug fortran/34228] New: -std=f* should diagnose used but later typed variables

[Bug fortran/34228] New: -std=f* should diagnose used but later typed variables

[burnus at gcc dot gnu dot org]

The following is frequently used and accepted by many compilers; thus it should
continue to work in -std=gnu, but - if feasible - one should reject it with
-std=f95/f2003.

  subroutine y
  data emname/'bar'/
  character(len=3) :: emname
  end subroutine y

Accepted by most compilers including the picky NAG f95. Rejected by g95:
  Symbol 'emname' at (1) being given type CHARACTER(1) already has implicit
type REAL(4)

"5.2.5 DATA statement
[...] A variable that appears in a DATA statement and has not been typed
previously may appear in a subsequent type declaration only if that declaration
confirms the implicit typing. An array name, array section, or array element
that appears in a DATA statement shall have had its array properties
established by a previous specification statement."

The part about DIMENSION is taken into account.

 * * *

  subroutine y(A,n)
    implicit none
    real :: A(n)
    integer :: n
  end subroutine y

This is invalid as "n" is first used and then typed. NAG f95 rejects it with:
  Error: Implicit type for N
  Error: Symbol N has already been implicitly typed
as other compilers accept this, it frequently occurs and should be allowed for
-std=gnu.

See:
F2003, 7.1.6 (Specification expression), pg 126
F95, 7.1.6.2 (Specification expression), pg 96

"A variable in a specification expression shall have its type and type
parameters, if any, specified by a previous declaration in the scoping
unit, by the implicit typing rules in effect for the scoping unit, or by
host association. If a variable in a specification expression is typed
by the implicit typing rules, its appearance in any subsequent type
declaration statement shall confirm the implicit type and type
parameters".


-- 
           Summary: -std=f* should diagnose used but later typed variables
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: enhancement
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[terry at chem dot gu dot se]

------- Comment #1 from terry at chem dot gu dot se  2007-11-27 22:12 -------
But a character string is not an array.  The len parameter is a type parameter.
 That part of the standard does not apply.  It's legal.


-- 

terry at chem dot gu dot se changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |terry at chem dot gu dot se


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[burnus at gcc dot gnu dot org]

------- Comment #2 from burnus at gcc dot gnu dot org  2007-11-27 22:16 -------
(In reply to comment #1)
> But a character string is not an array. The len parameter is a type parameter.
> That part of the standard does not apply. It's legal.

I don't worry about "len=3", I'm worrying about the type:

  data emname/'bar'/

is implicitly types REAL and then one line later comes:

  character(len=3) :: emname

I still think that this violates: "A variable that appears in a DATA statement
and has not been typed previously may appear in a subsequent type declaration
only if that declaration confirms the implicit typing."


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[terry at chem dot gu dot se]

------- Comment #3 from terry at chem dot gu dot se  2007-11-27 22:23 -------
> I don't worry about "len=3", I'm worrying about the type:
> 
>   data emname/'bar'/
> 
> is implicitly types REAL and then one line later comes:
> 
>   character(len=3) :: emname
> 
> I still think that this violates: "A variable that appears in a DATA statement
> and has not been typed previously may appear in a subsequent type declaration
> only if that declaration confirms the implicit typing."

Ah, yes, you're right.  I misinterpreted your concern.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[fxcoudert at gcc dot gnu dot org]

-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-11-29 11:24:37
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[domob at gcc dot gnu dot org]

-- 

domob at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |domob at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-11-29 11:24:37         |2008-08-01 08:26:38
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[domob at gcc dot gnu dot org]

------- Comment #4 from domob at gcc dot gnu dot org  2008-08-22 07:14 -------
Subject: Bug 34228

Author: domob
Date: Fri Aug 22 07:13:25 2008
New Revision: 139425

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=139425
Log:
2008-08-22  Daniel Kraft  <d@domob.eu>

        PR fortran/32095
        PR fortran/34228
        * gfortran.h (in_prefix): New global.
        (gfc_check_symbol_typed), (gfc_check_expr_typed): New methods.
        * array.c (match_array_element_spec): Check that bounds-expressions
        don't have symbols not-yet-typed in them.
        * decl.c (var_element): Check that variable used is already typed.
        (char_len_param_value): Check that expression does not contain
        not-yet-typed symbols.
        (in_prefix): New global.
        (gfc_match_prefix): Record using `in_prefix' if we're at the moment
        parsing a prefix or not.
        * expr.c (gfc_expr_check_typed): New method.
        * parse.c (verify_st_order): New argument to disable error output.
        (check_function_result_typed): New helper method.
        (parse_spec): Check that the function-result declaration, if given in
        a prefix, contains no not-yet-typed symbols when the IMPLICIT rules are
        parsed.
        * symbol.c (gfc_check_symbol_typed): Check that a symbol already has
        a type associated to it, otherwise use the IMPLICIT rules or signal
        an error.

2008-08-22  Daniel Kraft  <d@domob.eu>

        PR fortran/32095
        PR fortran/34228
        * gfortran.dg/used_before_typed_1.f90: New test.
        * gfortran.dg/used_before_typed_2.f90: New test.
        * gfortran.dg/used_before_typed_3.f90: New test.
        * gfortran.dg/array_constructor_26.f03: Add -std=gnu to not enable
        legacy-behaviour for the new check.
        * gfortran.dg/array_constructor_27.f03: Ditto.
        * gfortran.dg/blockdata_4.f90: Ditto.
        * gfortran.dg/bound_2.f90: Reordered declarations to satisfy the check.
        * gfortran.dg/result_in_spec_1.f90: Ditto.
        * gfortran.dg/argument_checking_7.f90: Adapted expected error messages.


Added:
    trunk/gcc/testsuite/gfortran.dg/used_before_typed_1.f90
    trunk/gcc/testsuite/gfortran.dg/used_before_typed_2.f90
    trunk/gcc/testsuite/gfortran.dg/used_before_typed_3.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/array.c
    trunk/gcc/fortran/decl.c
    trunk/gcc/fortran/expr.c
    trunk/gcc/fortran/gfortran.h
    trunk/gcc/fortran/parse.c
    trunk/gcc/fortran/symbol.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/argument_checking_7.f90
    trunk/gcc/testsuite/gfortran.dg/array_constructor_26.f03
    trunk/gcc/testsuite/gfortran.dg/array_constructor_27.f03
    trunk/gcc/testsuite/gfortran.dg/blockdata_4.f90
    trunk/gcc/testsuite/gfortran.dg/bound_2.f90
    trunk/gcc/testsuite/gfortran.dg/result_in_spec_1.f90


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[domob at gcc dot gnu dot org]

------- Comment #5 from domob at gcc dot gnu dot org  2008-08-22 07:17 -------
Fixed.


-- 

domob at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

[Bug fortran/34228] -std=f* should diagnose used but later typed variables

[mikael at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34228

--- Comment #6 from Mikael Morin <mikael at gcc dot gnu.org> 2011-09-07 21:42:17 UTC ---
*** Bug 29813 has been marked as a duplicate of this bug. ***