non-standard-file-extension (S091)

This rule is turned on by default.

What it does

Checks for use of standard file extensions.

Why is it bad?

The standard file extensions for modern (free-form) Fortran are '.f90' or '.F90'. Forms that reference later Fortran standards such as '.f08' or '.F95' may be rejected by some compilers and build tools.

The file extension '.pf' is permitted for users of the pFUnit testing framework.