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?
A Resolver *always* has a module scope at the end of its scope stack,
instead of encoding this as an invariant we can just lift this scope
out into a field, allowing us to skip going through the scope vec
indirection entirely.
feat: Implement `feature(exhaustive_patterns)` from unstable Rust
Closes#12753
Recognize Rust's unstable `#![feature(exhaustive_patterns)]` (RFC 1872). Allow omitting visibly uninhabited variants from `match` expressions when the feature is on.
This adjusts match checking to the current implementation of the postponed RFC 1872 in rustc.
This hir expression isn't needed and only existed as it was simpler to
deal with at first as it gave us a direct mapping for the ast version of
the same construct. This PR removes it, properly handling the statements
that are introduced by macro call expressions.
This PR will fix some typos detected by [typos].
There are also some other typos in the function names, variable names, and file
names, which I leave as they are. I'm more certain that typos in comments
should be fixed.
[typos]: https://github.com/crate-ci/typos
fix: Fix incorrect type mismatch with `cfg_if!` and other macros in expression position
Fixes https://github.com/rust-lang/rust-analyzer/issues/12940
This is a bit of a hack, ideally `MacroStmts` would not exist at all after HIR lowering, but that requires changing how the lowering code works.
fix: make `concat!` work with char
Fixes#12921
- I avoided making `unquote_str()` take char literals as well because it's depended on by another function `parse_string()` that's only supposed to take strings.
- Even with this patch, we don't output `\0` as `\u{0}` which #12921 pointed out ~~, but we're not actually responsible for serializing it but rowan is~~. They are functionally equivalent and I don't think it'd cause any confusion, but we *could* try escaping them before serialization (for reference, `rustc -Zunpretty=expanded`, which `cargo expand` uses under the hood, [makes use of `str::escape_default()`](3830ecaa8d/compiler/rustc_ast/src/util/literal.rs (L161)).
