Module names and file names are completely independent on the
language level. You can have a file `whatever.d` with `module
foo.bar.totally.different;` and `import
foo.bar.totally.different` and it all works as long as you add
the whatever.d to the build.
The only reason people recommend they match is that then the file
can be found automatically.
dmd program.d whatever.d # works from module names
dmd -i program.d # now it will look for
foo/bar/totally/different.d by convention because you didn't list
the file.
That one `import p;` is kinda weird, it should probably complain
then you imported one thing and got another, but generally the
name not matching is no problem at all.
