[m-rev.] for post-commit review: document source file dir field

[Julien Fischer]

On Sat, 14 Aug 2021, Zoltan Somogyi wrote:

> Document the source file dir field.
> 
> compiler/module_imports.m:
>     As above.
> 
> compiler/grab_modules.m:
>     Delete the XXXs about that field.

> diff --git a/compiler/module_imports.m b/compiler/module_imports.m
> index a06eac868..7ad9dbaa9 100644
> --- a/compiler/module_imports.m
> +++ b/compiler/module_imports.m
> @@ -175,16 +175,34 @@
>      --->    module_baggage(
>                  % The name of the source file and directory
>                  % containing the module source.
> -                % XXX I (zs) don't see source_file_dir being set to
> -                % anything but dir.this_directory.
> +                %
> +                % Currently, the source_file dir field is *always* set
> +                % to dir.this_directory, so strictly speaking, this field
> +                % is redundant. However, there arguments for keeping it.

     there *are* arguments ...

That's fine otherwise.

Julien.