feat: Display the value of enum variant on hover
fixes#12955
This PR adds const eval support for enums, as well as showing their value on hover, just as consts currently have.
I developed these two things at the same time, but I've realized now that they are separate. However since the hover is just a 10 line change (not including tests), I figured I may as well put them in the same PR. Though if you want them split up into "enum const eval support" and "show enum variant value on hover", I think that's reasonable too.
Since this adds const eval support for enums this also allows consts that reference enums to have their values computed now too.
The const evaluation itself is quite rudimentary, it doesn't keep track of the actual type of the enum, but it turns out that Rust doesn't actually either, and `E::A as u8` is valid regardless of the `repr` on `E`.
It also doesn't really care about what expression the enum variant contains, it could for example be a string, despite that not being allowed, but I guess it's up to the `cargo check` diagnostics to inform of such issues anyway?
Allow configuration of annotation location.
I've added the ability to configure where lens annotations render relevant to the item they describe. Previously, these would render directly above the line the item is declared on. Now, there is the ability to render these annotations above the entire item (including doc comments, and attributes).
The names of the config options are up for debate, I did what seemed best to me but if anyone has better ideas let me know.
This is my first contribution so if I've missed anything please let me know.
Here's a preview of what the new option looks like:
<img width="577" alt="Screen Shot 2022-09-11 at 10 39 51 PM" src="https://user-images.githubusercontent.com/33100798/189570298-b4fcbf9c-ee49-4b79-aae6-1037ae4f26af.png">
closes https://github.com/rust-lang/rust-analyzer/issues/13218
fix: handle lifetime variables in projection normalization
Fixes#12674
The problem is that we've been skipping the binders of normalized projections assuming they should be empty, but the assumption is unfortunately wrong. We may get back lifetime variables and should handle them before returning them as normalized projections. For those who are curious why we get those even though we treat all lifetimes as 'static, [this comment in chalk](d875af0ff1/chalk-solve/src/infer/unify.rs (L888-L908)) may be interesting.
I thought using `InferenceTable` would be cleaner than the other ways as it already has the methods for canonicalization, normalizing projection, and resolving variables, so moved goal building and trait solving logic to a new `HirDatabase` query. I made it transparent query as the query itself doesn't do much work but the eventual call to `HirDatabase::trait_solve_query()` does.
Previously, annotations would only appear above the name of an item (function signature, struct declaration, etc).
Now, rust-analyzer can be configured to show annotations either above the name or above the whole item (including doc comments and attributes).
fix: Insert whitespaces into static & const bodies if they are expanded from macro on hover
Partially fixes#13143.
To resolve the other part we need to expand macros in unevaluated static & const bodies, and I'm not sure we want to. If for example it includes a call to `assert!()`, expanding it will lead to worse hover.
fix: sort and deduplicate auto traits in trait object types
Fixes#12739
Chalk solver doesn't sort and deduplicate auto traits in trait object types, so we need to handle them ourselves in the lowering phase, just like [`rustc`](880416180b/compiler/rustc_typeck/src/astconv/mod.rs (L1487-L1488)) and [`chalk-integration`](https://github.com/rust-lang/chalk/blob/master/chalk-integration/src/lowering.rs#L575) do.
Quoting from [the Chalk book](https://rust-lang.github.io/chalk/book/types/rust_types.html#dyn-types):
> Note that -- for this purpose -- ordering of bounds is significant. That means that if you create a `dyn Foo + Send` and a `dyn Send + Foo`, chalk would consider them distinct types. The assumption is that bounds are ordered in some canonical fashion somewhere else.
Also, trait object types with more than one non-auto traits were previously allowed, but are now disallowed with this patch.
Make use of NoHash hashing for FileId and CrateId
Both of these are mere integers so there is nothing to hash here.
Ideally we would use this for `la_arena::Idx` too, but that doesn't work due to the orphan rule, and `la_arena` is unfortunately a public library so we can't really do much here... Unless we remove the trait restriction but I'd like not to
