Nvfortran 24.3 false warning for namelist variable that is also a dummy argument

Accelerated Computing HPC Compilers nvc, nvc++ and nvfortran
1

Here’s a reproducer:

module bug0003_mod

implicit none

public :: a

contains

subroutine a(x)
    real, intent(in) :: x
    
    ! Comment out the namelist line and nvfortran removes the false warning.
    namelist /bugnml/ x
    
    write(*, *) x
end subroutine a

end module bug0003_mod

program bug0003

use bug0003_mod, only: a
implicit none

call a(1.0)

end program bug0003

I think nvfortran has a false warning when compiling:

$ nvfortran --version

nvfortran 24.3-0 64-bit target on x86-64 Linux -tp haswell 
NVIDIA Compilers and Tools
Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES.  All rights reserved.
$ nvfortran bug0003.f90 
NVFORTRAN-W-0194-INTENT(IN) argument cannot be defined - x (bug0003.f90)
  0 inform,   1 warnings,   0 severes, 0 fatal for bug0003

Maybe this code isn’t standards compliant, so in that case the warning isn’t false. I’m not an expert on that, but I did search for namelist in the most recent standards document and didn’t see anything forbidding this. I can say that neither gfortran or ifx have any warnings or errors when compiled with standards checking and all the pedantic warnings enabled. And the warning message doesn’t make sense as x is defined.

Here’s a previous bug that seems similar: https://forums.developer.nvidia.com/t/incorrect-warning-for-intent-in-pointer-to-type-in-nvfortran-22-1/201471

2

Thanks btrettel2.

I filed this as TPR #35450 and will have engineering take a look.

-Mat

3

Hi btrettel2,

I’ve verified that TPR#35450 has been fixed in our 24.7 release:

 % nvfortran -V24.5 -c test.f90
NVFORTRAN-W-0194-INTENT(IN) argument cannot be defined - x (test.f90)
  0 inform,   1 warnings,   0 severes, 0 fatal for bug0003
% nvfortran -V24.7 -c test.f90
%

-Mat