`Deref`/`DerefMut` can be useful, but they can also obfuscate. I don't
think they're worth it for `RegionConstraintCollector`. They're also not
present on the similar types `OpaqueTypeTable` and `TypeVariableTable`.
`LeakCheck` can own `mini_graph` and `rcc` instead of holding references
to them. This requires inlining `assign_scc_value` to avoid a borrowck
error, but that's fine because it has a single call site.
It's a weird method, and used weirdly:
- It's on `RegionConstraintCollector` but operates on
`RegionConstraintStorage`. So at both call sites we create a temporary
`RegionConstraintCollector`, using `with_log`, to call it.
- It `take`s just two of the six fields in `RegionConstraintStorage`.
At one of the two call sites we unnecessarily clone the entire
`RegionConstraintStorage` just to take those two fields.
This commit just inlines and removes it. We no longer need to `take` the
two fields, we can just use them directly.
`OutlivesEnvironment::new` can call `OutlivesEnvironment::with_bounds`
with an empty `extra_bounds`. And once that's done,
`OutlivesEnvironmentBuilder` has a single use and can be inlined and
removed into `OutlivesEnvironment::with_bounds`.
Remove `CombineFields`
This conflicts with #131263, but if this one lands first then perhaps #131263 could then go ahead and remove all the branching on solver in `TypeRelating`. We could perhaps then rename `TypeRelating` to `OldSolverRelating` or something, idk.
r? lcnr
`FixupError` is isomorphic with `TyOrConstInferVar`, so this commit
changes it to just be a wrapper around `TyOrConstInferVar`.
Also, move the `Display` impl for `FixupError` next to `FixupError`.
Three of the modules don't need to be `pub`, and then
`warn(unreachable_pub)` identifies a bunch more things that also
shouldn't be `pub`, plus a couple of things that are unused.
Stabilize the `map`/`value` methods on `ControlFlow`
And fix the stability attribute on the `pub use` in `core::ops`.
libs-api in https://github.com/rust-lang/rust/issues/75744#issuecomment-2231214910 seemed reasonably happy with naming for these, so let's try for an FCP.
Summary:
```rust
impl<B, C> ControlFlow<B, C> {
pub fn break_value(self) -> Option<B>;
pub fn map_break<T>(self, f: impl FnOnce(B) -> T) -> ControlFlow<T, C>;
pub fn continue_value(self) -> Option<C>;
pub fn map_continue<T>(self, f: impl FnOnce(C) -> T) -> ControlFlow<B, T>;
}
```
Resolves#75744
``@rustbot`` label +needs-fcp +t-libs-api -t-libs
---
Aside, in case it keeps someone else from going down the same dead end: I looked at the `{break,continue}_value` methods and tried to make them `const` as part of this, but that's disallowed because of not having `const Drop`, so put it back to not even unstably-const.
Most of the code in these two modules is duplicated in the other module.
This commit eliminates the duplication by replacing them with a new
module `lattice_op`. The new `LatticeOpKind` enum is used to distinguish
between glb and lub in the few places where the behaviour differs.
add caching to most type folders, rm region uniquification
Fixes the new minimization of the hang in nalgebra and nalgebra itself :3
this is a bit iffy, especially the cache in `TypeRelating`. I believe all the caches are correct, but it definitely adds some non-local complexity in places. The first commit removes region uniquification, reintroducing the ICE from https://github.com/rust-lang/trait-system-refactor-initiative/issues/27. This does not affect coherence and I would like to fix this by introducing OR-region constraints
r? `@compiler-errors`
