[Bug fortran/30876] New: incorrect error message for valid code

[Bug fortran/30876] New: incorrect error message for valid code

[jv244 at cam dot ac dot uk]

With recent trunk, gfortran incorrectly generates an error for the following
standard code:
MODULE M1
CONTAINS
 FUNCTION correct_input(i)
   INTEGER :: i,correct_input(5)
   IF (i<1) correct_input=test(1)
   IF (i>5) correct_input=test(5)
 END FUNCTION correct_input

 RECURSIVE FUNCTION test(i)
  INTEGER :: test(5),i,j
  IF (i<1 .OR. i>5) THEN
    test=correct_input(i)
  ELSE
    test=0
    test(1:6-i)=(/(j,j=i,5)/)
    test=test(3)
  ENDIF
 END FUNCTION

END MODULE M1

USE M1
IF (ANY(TEST(3).NE.(/5,5,5,5,5/))) CALL ABORT()
IF (ANY(TEST(6).NE.(/0,0,0,0,0/))) CALL ABORT()
END


-- 
           Summary: incorrect error message for valid code
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jv244 at cam dot ac dot uk


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2007-02-20 16:28 -------
Compiles with nagf95 and g95.

ifort and gfortran give however the following error messages:

    test=test(3)
            1
Error: 'test' is array valued and directly recursive at (1) , so the keyword
RESULT must be specified in the FUNCTION statement

and

fortcom: Warning: dtgv.f90, line 9: Recursive array-valued function without
result variable ambiguous   [TEST]
 RECURSIVE FUNCTION test(i)
--------------------^
fortcom: Error: dtgv.f90, line 15: A recursive function name must not be used
in this context.   [TEST]
    test(1:6-i)=(/(j,j=i,5)/)
----^
fortcom: Error: dtgv.f90, line 15: A colon (:) is not valid in this context.  
[1]
    test(1:6-i)=(/(j,j=i,5)/)
---------^


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu dot
                   |                            |org
           Keywords|                            |rejects-valid
            Summary|incorrect error message for |Array valued recursive
                   |valid code                  |function rejected


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

------- Comment #2 from pault at gcc dot gnu dot org  2007-02-21 16:33 -------

> fortcom: Warning: dtgv.f90, line 9: Recursive array-valued function without
> result variable ambiguous   [TEST]

Goes right to the nub of it.  Within test, is an r-value expression that
contains a reference to  test (<int_expr>) a reference to the function result
array or a recursive call to test?

Paul


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[burnus at gcc dot gnu dot org]

------- Comment #3 from burnus at gcc dot gnu dot org  2007-02-21 17:03 -------
Paul,

> > fortcom: Warning: dtgv.f90, line 9: Recursive array-valued function without
> > result variable ambiguous   [TEST]
> Goes right to the nub of it.  Within test, is an r-value expression that
> contains a reference to  test (<int_expr>) a reference to the function result
> array or a recursive call to test?

Well, it is easy:
"12.5.2.1 Function subprogram"
"If RESULT is not specified, the result variable is <function- name> and all
occurrences of the function name in execution-part statements are references to
the result variable."

See also:
http://gcc.gnu.org/ml/fortran/2006-05/msg00342.html


-- 

burnus 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         |2007-02-21 17:03:09
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

------- Comment #4 from pault at gcc dot gnu dot org  2007-02-21 18:52 -------
Tobias,

> Well, it is easy:
> "12.5.2.1 Function subprogram"
> "If RESULT is not specified, the result variable is <function- name> and all
> occurrences of the function name in execution-part statements are references to
> the result variable."

Ahhhh! OK, thanks - I can feel a patch coming on.

Paul


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[fxcoudert at gcc dot gnu dot org]

------- Comment #5 from fxcoudert at gcc dot gnu dot org  2007-03-22 00:22 -------
(In reply to comment #3)
> "12.5.2.1 Function subprogram"
> "If RESULT is not specified, the result variable is <function- name> and all
> occurrences of the function name in execution-part statements are references to
> the result variable."

Then, the following should be invalid and rejected, shouldn't it?

recursive function f(i)
  integer :: f, i
  f = 0
  if (i > 0) f = f(i-1) + 1
end function

If every occurence of f is a reference to the variable result, it's strictly
equivalent to the following, clearly invalid code:

recursive function f(i) result(g)
  integer :: g, i
  g = 0
  if (i > 0) g = g(i-1) + 1
end function


-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fxcoudert at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[burnus at gcc dot gnu dot org]

------- Comment #6 from burnus at gcc dot gnu dot org  2007-03-22 07:41 -------
(In reply to comment #5)
> Then, the following should be invalid and rejected, shouldn't it?
> recursive function f(i)
>   integer :: f, i
>   f = 0
>   if (i > 0) f = f(i-1) + 1
> end function

NAG f95:
  line 4: Recursive invocation of F which has no RESULT clause
(gfortran and ifort allow this)

> recursive function f(i) result(g)
>   integer :: g, i
>   g = 0
>   if (i > 0) g = g(i-1) + 1
> end function

NAG f95: Inconsistent usage of G
ifort: This name has not been declared as an array or a function
gfortran: Cannot assign to a named constant


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

------- Comment #7 from pault at gcc dot gnu dot org  2007-05-08 13:51 -------
I'll submit a fix tonight.

Paul


-- 

pault at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

------- Comment #8 from pault at gcc dot gnu dot org  2007-05-08 13:52 -------
Oops!


-- 

pault at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |pault at gcc dot gnu dot org
                   |dot org                     |
             Status|REOPENED                    |ASSIGNED
   Last reconfirmed|2007-02-21 17:03:09         |2007-05-08 13:53:03
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[patchapp at dberlin dot org]

------- Comment #9 from patchapp at dberlin dot org  2007-05-10 08:13 -------
Subject: Bug number Pr30876

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2007-05/msg00579.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

------- Comment #11 from pault at gcc dot gnu dot org  2007-05-11 12:47 -------
Fixed on trunk

Paul


-- 

pault at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876

[Bug fortran/30876] Array valued recursive function rejected

[pault at gcc dot gnu dot org]

------- Comment #10 from pault at gcc dot gnu dot org  2007-05-11 12:47 -------
Subject: Bug 30876

Author: pault
Date: Fri May 11 11:46:47 2007
New Revision: 124616

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=124616
Log:
2007-05-11 Paul Thomas <pault@gcc.gnu.org>

        PR fortran/30876
        * trans-expr.c (gfc_conv_function_call): Reduce indirection for
        direct assignments of recursive array valued functions.
        * primary.c (gfc_match_rvalue): Correct error for recursive
        function calls such that directly recursive calls of scalar
        function without an explicit result are disallowed.

2007-05-11 Paul Thomas <pault@gcc.gnu.org>

        PR fortran/30876
        * gfortran.dg/recursive_reference_1.f90: Put error at correct
        line.
        * gfortran.dg/recursive_reference_2.f90: New test.


Added:
    trunk/gcc/testsuite/gfortran.dg/recursive_reference_2.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/primary.c
    trunk/gcc/fortran/trans-expr.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/recursive_reference_1.f90


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30876