https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91557
Bug ID: 91557
Summary: [7/8/9/10 Regression] Bogus warning about unused dummy
argument _formal_*
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: gs...@t-online.de
Target Milestone: ---
There is an _old_ issue with -Wall (-Wunused-dummy-argument)
and _legal_ code with contained procedures.
It does not depend on specific types.
Starting with z0.f90 and refactoring it to z1.f90 :
$ cat z0.f90
program p
integer :: a, b
a = 1
call g (a, b)
end
subroutine g (a, b)
integer :: a, b
integer :: x, y
call h (x, y)
if ( a > 0 ) y = y - 1
b = y - x + 1
end
$ gfortran-10-20190825 -c z0.f90 -Wall
$
$ cat z1.f90
program p
integer :: a, b
a = 1
call g
contains
subroutine g
integer :: x, y
call h (x, y)
if ( a > 0 ) y = y - 1
b = y - x + 1
end
end
$ gfortran-6 -c z1.f90 -Wall
$
$ gfortran-7 -c z1.f90 -Wall
z1.f90:8:19:
call h (x, y)
1
Warning: Unused dummy argument '_formal_0' at (1) [-Wunused-dummy-argument]
z1.f90:8:19:
call h (x, y)
1
Warning: Unused dummy argument '_formal_1' at (1) [-Wunused-dummy-argument]
$ gfortran-10-20190825 -c z1.f90 -Wall
z1.f90:9:19:
9 | call h (x, y)
| 1
Warning: Unused dummy argument '_formal_2' at (1) [-Wunused-dummy-argument]
z1.f90:9:19:
9 | call h (x, y)
| 1
Warning: Unused dummy argument '_formal_3' at (1) [-Wunused-dummy-argument]
The numbering (0/1->2/3) has changed between 20190818 and 20190825.
Might be one root cause of pr91556.
