Split MIR building into its own crate
This moves `rustc_mir::{build, hair, lints}` to `rustc_mir_build`.
The new crate only has a `provide` function as it's public API.
Based on #67898
cc @Centril @rust-lang/compiler
r? @oli-obk
Move more of `rustc::lint` into `rustc_lint`
Based on https://github.com/rust-lang/rust/pull/67806.
Here we try to consolidate more of the linting infra into `rustc::lint`. Some high-level notes:
- We now store an `Lrc<dyn Any + Send + Sync>` as opposed to `Lrc<LintStore>` in the `GlobalCtxt`. This enables us to avoid referring to the type, breaking a cyclic dependency, and so we can move things from `rustc::lint` to `rustc_lint`.
- `in_derive_expansion` is, and needs to, be moved as a method on `Span`.
- We reduce the number of ways on `tcx` to emit a lint so that the developer UX is more streamlined.
- `LintLevelsBuilder` is moved to `rustc_lint::levels`, leaving behind `LintLevelMap/Set` in a purified form due to current constraints (hopefully fixable in the future after https://github.com/rust-lang/rust/pull/68133).
- `struct_lint_level` is moved to `rustc::lint` due to current dependency constraints.
- `rustc::lint::context` is moved to `rustc_lint::context`.
- The visitors in `rustc::lint` are moved to `rustc_lint::passes`.
Introduce `X..`, `..X`, and `..=X` range patterns
Tracking issue: https://github.com/rust-lang/rust/issues/67264
Feature gate: `#![feature(half_open_range_patterns)]`
---------------------------
In this PR, we introduce range-from (`X..`), range-to (`..X`), and range-to-inclusive (`..=X`) patterns.
These correspond to the `RangeFrom`, `RangeTo`, and `RangeToInclusive` expression forms introduced with the same syntaxes. The correspondence is both syntactic and semantic (in the sense that e.g. a `X..` pattern matching on a scrutinee `s` holds exactly when `(X..).contains(&s)` holds).
---------------------------
Noteworthy:
- The compiler complexity added with this PR is around 10 lines (discounting new tests, which account for the large PR size).
- `...X` is accepted syntactically with the same meaning as `..=X`. This is done primarily to simplify and unify the implementation & spec. If-and-when we decide to make `X...Y` a hard error on a new edition, we can do the same for `...X` patterns as well.
- `X...` and `X..=` is rejected syntactically just like it is for the expression equivalents. We should perhaps make these into semantic restrictions (cc @petrochenkov).
- In HAIR, these half-open ranges are represented by inserting the max/min values for the approprate types. That is, `X..` where `X: u8` would become `X..=u8::MAX` in HAIR (note the `..=` since `RangeFrom` includes the end).
- Exhaustive integer / char matching does not (yet) allow for e.g. exhaustive matching on `0usize..` or `..5usize | 5..` (same idea for `isize`). This would be a substantially more invasive change, and could be added in some other PR.
- The issues with slice pattern syntax has been resolved as we decided to use `..` to mean a "rest-pattern" and `[xs @ ..]` to bind the rest to a name in a slice pattern.
- Like with https://github.com/rust-lang/rust/pull/35712, which provided `X..Y` range patterns, this is not yet backed up by an RFC. I'm providing this experimental implementation now to have something concrete to discuss. I would be happy to provide an RFC for this PR as well as for #35712 to finalize and confirm the ideas with the larger community.
Closes https://github.com/rust-lang/rfcs/issues/947.
---------------------------
r? @varkor cc @matthewjasper @oli-obk
I would recommend reviewing this (in particular HAIR-lowering and pattern parsing changes) with whitespace changes ignored.
rustc_ast_lowering: misc cleanup & rustc dep reductions
- The first two commits do some code simplification.
- The next three do some file splitting (getting `lib.rs` below the 3kloc tidy lint).
- The remaining commits reduce the number of `rustc::` imports. This works towards making lowering independent of the `rustc` crate.
r? @oli-obk cc @Zoxc
Treat extern statics just like statics in the "const pointer to static" representation
fixes#67612
r? @spastorino
cc @RalfJung this does not affect runtime promotion at all. This is just about promotion within static item bodies.
Move `is_min_const_fn` query to librustc_mir.
The only two uses of the associated methods are in `librustc_mir` and
`librustdoc`. Please tell me if there is a better choice.
cc #65031
Fix ICE in const pretty printing and resolve FIXME
Consts now have a `fmt::Display` impl, so we can just use that to pretty-print.
This resolves an ICE in https://github.com/rust-lang/rust/issues/61936, though it hits more ICEs afterwards. I couldn't find a test case that was resolved by this that didn't hit errors later on.
