https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115151
Bug ID: 115151
Summary: procedure(acos) [,pointer] :: p - is wrongly rejected
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
Target Milestone: ---
IT looks as if the following is wrongly rejected:
procedure(acos) [,pointer] :: p
While the examples below are with 'pointer', I don't see why it shouldn't be
also valid without 'pointer', but I have not verified it.
But I have to admit that I also have not fully understood C1218 – as I don't
see how one could ever specify something else - it either is by construction an
external procedure or it clashes name wise.
Only:
procedure(acos)[,pointer] :: acos
does not make sense as the former pulls in an 'intrinsic :: acos'.
* * *
Found at https://github.com/klausler/fortran-wringer-tests/ which has several
corner case testcases.
Testcase: acos-iface.f90
-------------
! Intel, NVF, NAG, f18: works
! GNU, XLF: errors about elemental or non-external procedure as interface
intrinsic :: acos
procedure(acos), pointer :: p
p => acos
print *, p(1.)
end
-------------
gfortran:
Error: Procedure pointer 'p' at (1) shall not be elemental
GCC's source code refers for this to F2008's ("15.4.3.6 Procedure declaration
statement"):
"C1218 (R1211) If a proc-interface describes an elemental procedure, each
procedure-entity-name shall specify an external procedure."
where
R1211 procedure-declaration-stmt is PROCEDURE ( [ proc-interface ] )7
[ [ , proc-attr-spec ] ... :: ] proc-decl -list
R1214 proc-decl is procedure-entity-name [ => proc-pointer-init ]
* * *
Furthermore, for procedure pointers, there is:
C1220 (R1217) The procedure-name shall be the name of a nonelemental external
or module procedure, or a specific intrinsic function listed in 13.6 and not
marked with a bullet (•).
where:
"R1216 proc-pointer-init is null-init
or initial-proc-target
R1217 initial-proc-target is procedure-name"
'acos' has no dot – and 13.6 has:
"Note that a specific function that is marked with a bullet (•) is not
permitted to be used as an actual argument (12.5.1, C1220), as a target in a
procedure pointer assignment statement (7.2.2.2, C729), or as the interface in
a procedure declaration statement (12.4.3.6, C1216)."
The latter implies that 'acos' is permitted on 'p => acos'.
* * *
Thus, the question is still whether C1218 makes sense for 'p', i.e. does it
apply to 'p' and (if so) is this is valid for proc pointers or not?
"C855 A named procedure with the POINTER attribute shall have the EXTERNAL
attribute." is in any case required for proc-pointers as well.
However, that's given by:
"A procedure declaration statement declares procedure pointers, dummy
procedures, and external procedures. It specifies the EXTERNAL attribute
(8.5.9) for all entities in the proc-decl-list."
Which means - unsurprisingly - that the following is invalid:
module m
contains
subroutine msub; end;
end
use m
intrinsic :: acos
pointer :: msub, intsub, acos ! INVALID
contains
subroutine intsub; end
end
