Allow different slug names for the same dynamic path

[ricokahler]

Feature request

Is your feature request related to a problem? Please describe.

I'm currently in the process of taking a WordPress site headless with Next.js (thanks to 9.3 🙌). In WordPress, there are pages and posts (among other entities) that can create URLs with slugs top level (e.g. https://example.com/my-blog-post/, https://example.com/some-page/). I think for SSG, it's reasonable to allow different templates for the same dynamic path scheme.

Describe the solution you'd like

I'd like to be able to do something like this:

/pages
--[post].tsx
--[page].tsx

It seems like this is possible if the getStaticPaths does not return conflicting paths and if either both (or possibly just one) file has fallback set to false.

Describe alternatives you've considered

I could get around this by adding some manual routing between the two different slugs but it requires get the paths and pulling them into the component to do matching.

Even if these pages share the same dynamic path, the component templates are different so it'd be nice if next would handle this case.

Additional context

Gatsby allows these kind of schemes already via their createPage API. I think that + the fact the WordPress has top-level URL slugs with different templates justifies implementing this.