I got caught with a wild goose chase with this one. I tried to get it
to work before seeing the standard reference in trans-expr.c. In fact,
it would be impossible to fix because there is no way to resolve
different instances of the abstract interface with different character
lengths.
Bootstrapped and regtested on FC28/x86_64 - OK for trunk.
I do not intend to backport it unless there is any enthusiasm for me to do so.
Regards
Paul
2018-06-19 Paul Thomas <pa...@gcc.gnu.org>
PR fortran/49630
* resolve.c (resolve_contained_fntype): Change standard ref.
from F95 to F2003: C418. Correct a spelling error in a comment.
It is an error for an abstract interface to have an assumed
character length result.
* trans-expr.c (gfc_conv_procedure_call): Likewise change the
standard reference.
2018-06-19 Paul Thomas <pa...@gcc.gnu.org>
PR fortran/49630
* gfortran.dg/assumed_charlen_function_7.f90: New test.
Index: gcc/fortran/resolve.c
===================================================================
*** gcc/fortran/resolve.c (revision 261126)
--- gcc/fortran/resolve.c (working copy)
*************** resolve_contained_fntype (gfc_symbol *sy
*** 601,609 ****
}
}
! /* Fortran 95 Draft Standard, page 51, Section 5.1.1.5, on the Character
type, lists the only ways a character length value of * can be used:
! dummy arguments of procedures, named constants, and function results
in external functions. Internal function results and results of module
procedures are not on this list, ergo, not permitted. */
--- 601,610 ----
}
}
! /* Fortran 2003 Draft Standard, page 535, C418, on type-param-value
type, lists the only ways a character length value of * can be used:
! dummy arguments of procedures, named constants, function results and
! in allocate statements if the allocate_object is an assumed length dummy
in external functions. Internal function results and results of module
procedures are not on this list, ergo, not permitted. */
*************** resolve_function (gfc_expr *expr)
*** 3103,3109 ****
return false;
}
! /* If this ia a deferred TBP with an abstract interface (which may
of course be referenced), expr->value.function.esym will be set. */
if (sym && sym->attr.abstract && !expr->value.function.esym)
{
--- 3104,3110 ----
return false;
}
! /* If this is a deferred TBP with an abstract interface (which may
of course be referenced), expr->value.function.esym will be set. */
if (sym && sym->attr.abstract && !expr->value.function.esym)
{
*************** resolve_function (gfc_expr *expr)
*** 3112,3117 ****
--- 3113,3129 ----
return false;
}
+ /* If this is a deferred TBP with an abstract interface, its result
+ cannot be an assumed length character (F2003: C418). */
+ if (sym && sym->attr.abstract && sym->attr.function
+ && sym->result->ts.u.cl->length == NULL)
+ {
+ gfc_error ("ABSTRACT INTERFACE %qs at %L must not have an assumed "
+ "character length result (F2003: C418)", sym->name,
+ &sym->declared_at);
+ return false;
+ }
+
/* Switch off assumed size checking and do this again for certain kinds
of procedure, once the procedure itself is resolved. */
need_full_assumed_size++;
Index: gcc/fortran/trans-expr.c
===================================================================
*** gcc/fortran/trans-expr.c (revision 261126)
--- gcc/fortran/trans-expr.c (working copy)
*************** gfc_conv_procedure_call (gfc_se * se, gf
*** 5941,5947 ****
{
if (ts.u.cl->length == NULL)
{
! /* Assumed character length results are not allowed by 5.1.1.5 of the
standard and are trapped in resolve.c; except in the case of SPREAD
(and other intrinsics?) and dummy functions. In the case of SPREAD,
we take the character length of the first argument for the result.
--- 5941,5947 ----
{
if (ts.u.cl->length == NULL)
{
! /* Assumed character length results are not allowed by C418 of the 2003
standard and are trapped in resolve.c; except in the case of SPREAD
(and other intrinsics?) and dummy functions. In the case of SPREAD,
we take the character length of the first argument for the result.
Index: gcc/testsuite/gfortran.dg/assumed_charlen_function_7.f90
===================================================================
*** gcc/testsuite/gfortran.dg/assumed_charlen_function_7.f90 (nonexistent)
--- gcc/testsuite/gfortran.dg/assumed_charlen_function_7.f90 (working copy)
***************
*** 0 ****
--- 1,34 ----
+ ! { dg-do compile }
+ !
+ ! Test the fix for PR49630, comment #11.
+ !
+ ! Contributed by Vittorio Zecca <zec...@gmail.com>
+ !
+ module abc
+ implicit none
+ type,abstract::abc_abstract
+ contains
+ procedure(abc_interface),deferred::abc_function
+ end type abc_abstract
+ type,extends(abc_abstract)::abc_type
+ contains
+ procedure::abc_function
+ end type abc_type
+ abstract interface
+ function abc_interface(this) ! { dg-error "assumed character length result" }
+ import abc_abstract
+ class(abc_abstract),intent(in)::this
+ character(len=*)::abc_interface
+ end function abc_interface
+ end interface
+ contains
+ function abc_function(this)
+ class(abc_type),intent(in)::this
+ character(len=5)::abc_function
+ abc_function="hello"
+ end function abc_function
+ subroutine do_something(this)
+ class(abc_abstract),intent(in)::this
+ print *,this%abc_function()
+ end subroutine do_something
+ end module abc
