Dear all,
Fortran 2018 added a clarification that the *result* of a function
whose result *variable* has the ALLOCATABLE attribute is a *value*
that itself does not have the ALLOCATABLE attribute.
For those interested: there was a thread on the J3 mailing list
some time ago (for links see the PR).
The patch which implements a related check was co-authored with
Steve and regtested by him. Testcase verified against NAG.
OK for mainline (gcc-14)?
Thanks,
Harald & Steve
From 2cebc8f9e7b399b7747c9ad0392831de91851b5b Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anl...@gmx.de>
Date: Thu, 20 Apr 2023 21:47:34 +0200
Subject: [PATCH] Fortran: function results never have the ALLOCATABLE
attribute [PR109500]
Fortran 2018 8.5.3 (ALLOCATABLE attribute) explains in Note 1 that the
result of referencing a function whose result variable has the ALLOCATABLE
attribute is a value that does not itself have the ALLOCATABLE attribute.
gcc/fortran/ChangeLog:
PR fortran/109500
* interface.cc (gfc_compare_actual_formal): Reject allocatable
functions being used as actual argument for allocable dummy.
gcc/testsuite/ChangeLog:
PR fortran/109500
* gfortran.dg/allocatable_function_11.f90: New test.
Co-authored-by: Steven G. Kargl <ka...@gcc.gnu.org>
---
gcc/fortran/interface.cc | 12 +++++++
.../gfortran.dg/allocatable_function_11.f90 | 36 +++++++++++++++++++
2 files changed, 48 insertions(+)
create mode 100644 gcc/testsuite/gfortran.dg/allocatable_function_11.f90
diff --git a/gcc/fortran/interface.cc b/gcc/fortran/interface.cc
index e9843e9549c..968ee193c07 100644
--- a/gcc/fortran/interface.cc
+++ b/gcc/fortran/interface.cc
@@ -3638,6 +3638,18 @@ gfc_compare_actual_formal (gfc_actual_arglist **ap, gfc_formal_arglist *formal,
goto match;
}
+ if (a->expr->expr_type == EXPR_FUNCTION
+ && a->expr->value.function.esym
+ && f->sym->attr.allocatable)
+ {
+ if (where)
+ gfc_error ("Actual argument for %qs at %L is a function result "
+ "and the dummy argument is ALLOCATABLE",
+ f->sym->name, &a->expr->where);
+ ok = false;
+ goto match;
+ }
+
/* Check intent = OUT/INOUT for definable actual argument. */
if (!in_statement_function
&& (f->sym->attr.intent == INTENT_OUT
diff --git a/gcc/testsuite/gfortran.dg/allocatable_function_11.f90 b/gcc/testsuite/gfortran.dg/allocatable_function_11.f90
new file mode 100644
index 00000000000..1a2831e186f
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/allocatable_function_11.f90
@@ -0,0 +1,36 @@
+! { dg-do compile }
+! PR fortran/109500 - check F2018:8.5.3 Note 1
+!
+! The result of referencing a function whose result variable has the
+! ALLOCATABLE attribute is a value that does not itself have the
+! ALLOCATABLE attribute.
+
+program main
+ implicit none
+ integer, allocatable :: p
+ procedure(f), pointer :: pp
+ pp => f
+ p = f()
+ print *, allocated (p)
+ print *, is_allocated (p)
+ print *, is_allocated (f()) ! { dg-error "is a function result" }
+ print *, is_allocated (pp()) ! { dg-error "is a function result" }
+ call s (p)
+ call s (f()) ! { dg-error "is a function result" }
+ call s (pp()) ! { dg-error "is a function result" }
+
+contains
+ subroutine s(p)
+ integer, allocatable :: p
+ end subroutine s
+
+ function f()
+ integer, allocatable :: f
+ allocate (f, source=42)
+ end function
+
+ logical function is_allocated(p)
+ integer, allocatable :: p
+ is_allocated = allocated(p)
+ end function
+end program
--
2.35.3
