rustdoc: Does not list impls on type aliases

[sdroege]

Happens with https://github.com/sdroege/gstreamer-rs/tree/52c013b8348ab3a98bb8475916aa306a3fc664de

If you check gstreamer/src/caps.rs, it has impl Caps, where type Caps = GstRc<CapsRef>. That one shows up in the rustdoc index (when searching), but neither on the Caps type alias docs, nor on the GstRc docs.

In gstreamer/src/buffer.rs there is impl GstRc<BufferRef>. That one shows up in the GstRc docs.

@GuillaumeGomez

[QuietMisdreavus]

That commit (nor the current master) does not contain an impl Caps block for rustdoc to pick up. It does have an impl GstRc<CapsRef>, which, when changed to impl Caps will properly show up on the Caps page, thanks to #42027. It does, however remove it from the GstRc page. If this is desired, this has been fixed. Otherwise it can be folded into #32077 since it would require more active work of substituting the full type when searching for impls.

[sdroege]

Having it only the the Caps page would be good enough for my taste. If it's on the GstRc page, there will be a lot of noise and it will be hard to find anything :)

[QuietMisdreavus]

Then I'll call this "fixed by #42027". 😀 If you change the impl blocks to point to the type alias instead of the expanded type, then render docs with a nightly compiler, the docs will show up the way you want them.

[sdroege]

Perfect, thanks :)