5971: Implement async blocks r=flodiebold a=oxalica
Fix#4018
@flodiebold already gave a generic guide in the issue. Here's some concern about implementation detail:
- Chalk doesn't support generator type yet.
- Adding generator type as a brand new type (ctor) can be complex and need to *re-introduced* builtin impls. (Like how we implement closures before native closure support of chalk, which is already removed in #5401 )
- The output type of async block should be known after type inference of the whole body.
- We cannot directly get the type from source like return-positon-impl-trait. But we still need to provide trait bounds when chalk asking for `opaque_ty_data`.
- During the inference, the output type of async block can be temporary unknown and participate the later inference.
`let a = async { None }; let _: i32 = a.await.unwrap();`
So in this PR, the type of async blocks is inferred as an opaque type parameterized by the `Future::Output` type it should be, like what we do with closure type.
And it really works now.
Well, I still have some questions:
- The bounds `AsyncBlockImplType<T>: Future<Output = T>` is currently generated in `opaque_ty_data`. I'm not sure if we should put this code here.
- Type of async block is now rendered as `impl Future<Output = OutputType>`. Do we need to special display to hint that it's a async block? Note that closure type has its special format, instead of `impl Fn(..) -> ..` or function type.
Co-authored-by: oxalica <oxalicc@pm.me>
`hir` should know nothing about URLs, markdown and html. It should
only be able to:
* resolve stringy path from documentation
* generate canonical stringy path for a def
In contrast, link rewriting should not care about semantics of paths
and names resolution, and should be concern only with text mangling
bits.
5643: Add new consuming modifier, apply consuming and mutable to methods r=matklad a=Nashenas88
This adds a new `consuming` semantic modifier for syntax highlighters.
This also emits `mutable` and `consuming` in two cases:
- When a method takes `&mut self`, then it now has `function.mutable` emitted.
- When a method takes `self`, and the type of `Self` is not `Copy`, then `function.consuming` is emitted.
CC @flodiebold
Co-authored-by: Paul Daniel Faria <Nashenas88@users.noreply.github.com>
Conjecture: it's impossible to use hir::Path *correctly* from an IDE.
I am not entirely sure about this, and we might need to add it back at
some point, but I have to arguments that convince me that we probably
won't:
* `hir::Path` has to know about hygiene, which an IDE can't set up
properly.
* `hir::Path` lacks identity, but you actually have to know identity
to resolve it correctly
