Properly infer types with type casts
This PR reenables `Expectation::Castable` (previous attempt at #14104, reverted by #14120) and implements type cast checks, which enable us to infer a bit more.
Castable expectations are relatively weak -- they only influence the inference if we cannot infer the types by other means. Therefore, we need to defer possible type unification with the casted type until we type check all expressions of the body. This PR adds a struct and slots in `InferenceContext` for the deferred cast checks (c.f. [`CastCheck`] in `rustc_hir_typeck`).
I only implemented the bits that affect the inference result. It should be possible to return type adjustments for well-formed casts and report diagnostics for invalid casts, but I'm leaving them for future work for now.
Fixes#11571Fixes#15246
[`CastCheck`]: da1d099f91/compiler/rustc_hir_typeck/src/cast.rs (L55)
Normalize expected ty in call arguments
fix#15321
I'm not sure if we should do this, or add a normalize in the beginning of `infer_expr_inner`, or somewhere else. r? `@lowr`
Report `incorrect-ident-case` for inner items
Fixes#15319
Although we have been collecting the diagnostics for inner items within function bodies, we were discarding them and never reported to the users. This PR makes sure that they are all reported and additionally collects the diagnostics for inner items within const bodies, static bodies, and enum variant bodies.
Pass `TraitEnvironment` into `layout_ty` and `const_eval`
We need to do either this or get rid of trait environment in `normalize_ty`. Let's go with this for now.
Make fields of mir::Terminator public
When trying to use the RA crate, I am unable to access the fields in `hir_def::mir::Terminator`.
I don't see any reason, why these should be private, especially as the fields of `hir_def::mir::Statement` are `pub`.
I am not sure if the fields in `hir_def::mir::SwitchTargets` should be made `pub` too, but at least they are read-accessible via some public methods..
Sorry if I missed something, this is my first PR.
Support GATs in bounds for associated types
Chalk has a dedicated IR for bounds on trait associated type: `rust_ir::InlineBound`. We have been failing to convert GATs inside those bounds from our IR to chalk IR. This PR provides an easy fix for it: properly take GATs into account during the conversion.
Map our diagnostics to rustc and clippy's ones
And control their severity by lint attributes `#[allow]`, `#[deny]` and ... .
It doesn't work with proc macros and I would like to fix that before merge but I don't know how to do it.
internal: Format let-else
As nightly finally got support for it I went ahead and formatted r-a with the latest nightly, then with the latest stable (in case other stuff changed)
Use anonymous lifetime where possible
Because anonymous lifetimes are *super* cool.
More seriously, I believe anonymous lifetimes, especially those in impl headers, reduce cognitive load to a certain extent because they usually signify that they are not relevant in the signature of the methods within (or that we can apply the usual lifetime elision rules even if they are relevant).
