Defer evaluating type system constants when they use infers or params
Split out of #137972, the parts necessary for associated const equality and min generic const args to make progress and have correct semantics around when CTFE is invoked. According to a [previous perf run](https://perf.rust-lang.org/compare.html?start=93257e2d20809d82d1bc0fcc1942480d1a66d7cd&end=01b4cbf0f47c3f782330db88fa5ba199bba1f8a2&stat=instructions:u) of adding the new `const_arg_kind` query we should expect minor regressions here.
I think this is acceptable as we should be able to remove this query relatively soon once mgca is more complete as we'll then be able to implement GCE in terms of mgca and rip out `GCEConst` at which point it's trivial to determine what kind of anon const we're dealing with (either it has generics and is a repeat expr hack, or it doesnt and is a normal anon const).
This should only affect unstable code as we handle repeat exprs specially and those are the only kinds of type system consts that are allowed to make use of generic parameters.
Fixes#133066Fixes#133199Fixes#136894Fixes#137813
r? compiler-errors
Rollup of 7 pull requests
Successful merges:
- #135562 (Add ignore value suggestion in closure body)
- #139635 (Finalize repeat expr inference behaviour with inferred repeat counts)
- #139668 (Handle regions equivalent to 'static in non_local_bounds)
- #140218 (HIR ty lowering: Clean up & refactor the lowering of type-relative paths)
- #140435 (use uX::from instead of _ as uX in non - const contexts)
- #141130 (rustc_on_unimplemented cleanups)
- #141286 (Querify `coroutine_hidden_types`)
Failed merges:
- #140247 (Don't build `ParamEnv` and do trait solving in `ItemCtxt`s when lowering IATs)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't allow `poly_select` in new solver
I added a `poly_select` call in #140519, but this causes an ICE since the new solver doesn't properly handle the "instantiate binder -> recanonicalize" step in the proof tree visitor.
While we could fix the select visitor to look at the next step in proof tree, it's not really necessary. Instead, let's enforce that all callees call the non-higher-ranked `select` function in the new solver.
Fixes https://github.com/rust-lang/rust/issues/141322
r? lcnr
Normalize aliases to correct kind of error term
Fixes#140642
When normalizing an alias to an error in the old solver, normalize to the same term kind as the alias being normalized instead of always to a type error.
r? lcnr
Fix `FnOnce` impl for `AsyncFn`/`AsyncFnMut` self-borrowing closures in new solver
This only affects closures that are "`AsyncFn`/`AsyncFnMut`" in their calling capability that are being called with the `FnOnce` trait.
fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/217
r? lcnr
Querify `coroutine_hidden_types`
This is necessary if we ever want to add implied bounds that would be used for higher-ranked coroutine auto trait goals (e.g. future implements `Send`).
Modest perf regression in `hyper` full build which (afaict?) is the only async stress test, so definitely worth it IMO.
r? oli-obk
Fast path for processing some obligations in the new solver
Fast path applies to:
- Dyn compatibility predicates
- Region and type outlives predicates
- Trivially sized predicates
Document why we allow escaping bound vars in LTA norm
r? lcnr
followup from the const normalization PR. I think I now understand why free alias norm is funny about binders
Rollup of 7 pull requests
Successful merges:
- #141267 (only resolve top-level guard patterns' guards once)
- #141280 (Use Docker cache from the current repository)
- #141296 (Async drop fix for 'broken mir, place has deref as later projection')
- #141328 (When AsyncDrop impl is empty, sync drop generated in elaborator)
- #141332 (Do not eagerly fold consts in `normalize_param_env_or_error` if new solver)
- #141333 (Use `DeepRejectCtxt` in `assemble_inherent_candidates_from_param`)
- #141334 (eagerly check nested obligations when coercing fndefs)
r? `@ghost`
`@rustbot` modify labels: rollup
Do not eagerly fold consts in `normalize_param_env_or_error` if new solver
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/213
Given:
```
trait Trait: Deref<Target = [u8; { 1 + 1 }]> {}
```
when elaborating param env for `Trait`, we have `Self: Trait`, `Self: Deref<Target = [u8; {anon const}]>`.
Before this PR, we would fold the anon consts away *before* elaborating. However, we end up getting another *un-folded* copy of the anon const from elaborating `Self: Trait`. This leads to normalization ambiguity.
r? lcnr
Match on lang item kind instead of using an if/else chain
Similar to how the new solver does this. Just noticed while I was adding a new entry to the chain 😆
Make well-formedness predicates no longer coinductive
This PR makes well-formedness no longer coinductive. It was made coinductive in https://github.com/rust-lang/rust/pull/98542, but AFAICT this was only to fix UI tests since we stopped lowering `where Ty:` to an empty-region outlives predicate but to a WF predicate instead.
Arguably it should lower to something completely different, something like a "type mentioned no-op predicate", but well-formedness serves this purpose fine today, and since no code (according to crater) relies on this coinductive behavior, we'd like to avoid having to emulate it in the new solver.
Fixes#123456 (I didn't want to add a test since it seems low-value to have a ICE test for a fuzzer minimization that is basically garbage code.)
Fixes#109764 (not sure if this behavior is emulatable w/o coinductive WF?)
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/169
r? lcnr
trait_sel: deep reject `match_normalize_trait_ref`
Spotted during an in-person review of #137944 at RustWeek: `match_normalize_trait_ref` could be using `DeepRejectCtxt` to exit early as an optimisation for projection candidates, like is done with param candidates.
r? `@lcnr`
cc `@oli-obk`
Use the new solver in the `impossible_predicates`
The old solver is unsound for many reasons. One of which was weaponized by `@lcnr` in #140212, where the old solver was incompletely considering a dyn vtable method to be impossible and replacing its vtable entry with a null value. This null function could be called post-mono.
The new solver is expected to be less incomplete due to its correct handling of higher-ranked aliases in relate. This PR switches the `impossible_predicates` query to use the new solver, which patches this UB.
r? lcnr
Stage0 bootstrap update
This PR [follows the release process](https://forge.rust-lang.org/release/process.html#master-bootstrap-update-tuesday) to update the stage0 compiler.
The only thing of note is 58651d1b31, which was flagged by clippy as a correctness fix. I think allowing that lint in our case makes sense, but it's worth to have a second pair of eyes on it.
r? `@Mark-Simulacrum`
Spotted during an in-person review of unrelated changes,
`match_normalize_trait_ref` could be using `DeepRejectCtxt` to exit early
as an optimisation for prejection candidates, like is done in param
candidates.
