a general type system cleanup
removes the helper functions `traits::fully_solve_X` as they add more complexity then they are worth. It's confusing which of these helpers should be used in which context.
changes the way we deal with overflow to always add depth in `evaluate_predicates_recursively`. It may make sense to actually fully transition to not have `recursion_depth` on obligations but that's probably a bit too much for this PR.
also removes some other small - and imo unnecessary - helpers.
r? types
Only clear written-to locals in ConstProp
This aims to revert the regression in https://github.com/rust-lang/rust/pull/108872
Clearing all locals at the end of each bb is very costly.
This PR goes back to the original implementation of recording which locals are modified.
Rollup of 8 pull requests
Successful merges:
- #96391 (Windows: make `Command` prefer non-verbatim paths)
- #108164 (Drop all messages in bounded channel when destroying the last receiver)
- #108729 (fix: modify the condition that `resolve_imports` stops)
- #109336 (Constrain const vars to error if const types are mismatched)
- #109403 (Avoid ICE of attempt to add with overflow in emitter)
- #109415 (Refactor `handle_missing_lit`.)
- #109441 (Only implement Fn* traits for extern "Rust" safe function pointers and items)
- #109446 (Do not suggest bounds restrictions for synthesized RPITITs)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Do not suggest bounds restrictions for synthesized RPITITs
Before this PR we were getting ...
```
warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
--> tests/ui/async-await/in-trait/missing-send-bound.rs:5:12
|
5 | #![feature(async_fn_in_trait)]
| ^^^^^^^^^^^^^^^^^
|
= note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
= note: `#[warn(incomplete_features)]` on by default
error: future cannot be sent between threads safely
--> tests/ui/async-await/in-trait/missing-send-bound.rs:17:20
|
17 | assert_is_send(test::<T>());
| ^^^^^^^^^^^ future returned by `test` is not `Send`
|
= help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `impl Future<Output = ()>`
note: future is not `Send` as it awaits another future which is not `Send`
--> tests/ui/async-await/in-trait/missing-send-bound.rs:13:5
|
13 | T::bar().await;
| ^^^^^^^^ await occurs here on type `impl Future<Output = ()>`, which is not `Send`
note: required by a bound in `assert_is_send`
--> tests/ui/async-await/in-trait/missing-send-bound.rs:21:27
|
21 | fn assert_is_send(_: impl Send) {}
| ^^^^ required by this bound in `assert_is_send`
help: consider further restricting the associated type
|
16 | fn test2<T: Foo>() where impl Future<Output = ()>: Send {
| ++++++++++++++++++++++++++++++++++++
error: aborting due to previous error; 1 warning emitted
```
and we want this output ...
```
warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/missing-send-bound.rs:5:12
|
LL | #![feature(async_fn_in_trait)]
| ^^^^^^^^^^^^^^^^^
|
= note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
= note: `#[warn(incomplete_features)]` on by default
error: future cannot be sent between threads safely
--> $DIR/missing-send-bound.rs:17:20
|
LL | assert_is_send(test::<T>());
| ^^^^^^^^^^^ future returned by `test` is not `Send`
|
= help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `impl Future<Output = ()>`
note: future is not `Send` as it awaits another future which is not `Send`
--> $DIR/missing-send-bound.rs:13:5
|
LL | T::bar().await;
| ^^^^^^^^ await occurs here on type `impl Future<Output = ()>`, which is not `Send`
note: required by a bound in `assert_is_send`
--> $DIR/missing-send-bound.rs:21:27
|
LL | fn assert_is_send(_: impl Send) {}
| ^^^^ required by this bound in `assert_is_send`
error: aborting due to previous error; 1 warning emitted
```
r? `@compiler-errors`
Only implement Fn* traits for extern "Rust" safe function pointers and items
Since calling the function via an `Fn` trait will assume `extern "Rust"` ABI and not do any safety checks, only safe `extern "Rust"` function can implement the `Fn` traits. This syncs the logic between the old solver and the new solver.
r? `@compiler-errors`
Constrain const vars to error if const types are mismatched
When equating two consts of different types, if either are const variables, constrain them to the correct const error kind.
This helps us avoid "successfully" matching a const against an impl signature but leaving unconstrained const vars, which will lead to incremental ICEs when we call const-eval queries during const projection.
Fixes#109296
The second commit in the stack fixes a regression in the first commit where we end up mentioning `[const error]` in an impl overlap error message. I think the error message changes for the better, but I could implement alternative strategies to avoid this without delaying the overlap error message...
r? `@BoxyUwU`
not *all* retags might be explicit in Runtime MIR
In https://github.com/rust-lang/rust/pull/105317 I made Miri treat `Rvalue::Ref/AddrOf` as implicit retagging sites. This updates the MIR docs accordingly.
For `Rvalue::Ref` I think this makes a lot more sense: creating a new reference is their entire point, so we can avoid bloating the MIR with retags. Also this seems to be the best way to handle cases like `*ptr = &[mut] ...`, where doing a retag is somewhat questionable since maybe `*ptr` points to another place now?
For `Rvalue::AddrOf`, Stacked Borrows needs this because even raw ptrs need some retagging, but Tree Borrows doesn't do ant retagging here and I hope we'll end up with a model where raw pointers don't get retagged.
Custom MIR: Support aggregate expressions
Add support for tuple, array and ADT expressions in custom mir
r? `````@oli-obk````` or `````@tmiasko````` or `````@JakobDegen`````
Walk un-shifted nested `impl Trait` in trait when setting up default trait method assumptions
Fixes a double subtraction in some binder math in return-position `impl Trait` in trait handling code.
Fixes#109239
new solver: make all goal evaluation able to be automatically rerun
It is generally wrong to call `evaluate_goal` multiple times or `evaluate_goal` and `evaluate_all` for the same `QueryResult` without correctly handling rerunning the goals when inference makes progress. Not doing so will result in the assertion in `evaluate_goal` firing because rerunning the goal will lead to a more accurate `QueryResult`.
Currently there are lots of places that get this wrong and generally it is complex and error prone to handle correctly everywhere. This PR introduces a way to add goals to the `EvalCtxt` and then run all the added goals in a loop so that `evaluate_goal`/`evaluate_all` is not necessary to call manually.
There are a few complications for making everything work "right":
1. the `normalizes-to` hack that replaces the rhs with an unconstrained infer var requires special casing in the new `try_evaluate_added_goals` function similar to how `evaluate_goal`'s assertion special cases that hack.
2. `assemble_candidates_after_normalizing_self_ty`'s normalization step needs to be reran for each candidate otherwise the found candidates will potentially get a more accurate `QueryResult` when rerunning the projection/trait goal which can effect the `QueryResult` of the projection/trait goal.
This is implemented via `EvalCtxt::probe`'s closure's `EvalCtxt` inheriting the added goals of the `EvalCtxt` that `probe` is called on, allowing us to add goals in a probe, and then enter a nested probe for each candidate and evaluate added goals which include the normalization step's goals.
I made `make_canonical_response` evaluate added goals so that it will be hard to mess up the impl of the solver by forgetting to evaluate added goals. Right now the only way to mess this up would be to call `response_no_constraints` (which from the name is obviously weird).
The visibility of `evaluate_goal` means that it can be called from various `compute_x_goal` or candidate assembly functions, this is generally wrong and we should never call `evaluate_goal` manually, instead we should be calling `add_goal`/`add_goals`. This is solved by moving `evaluate_goal` `evaluate_canonical_goal` and `compute_goal` into `eval_ctxt`'s module and making them private so they cannot be called from elsewhere, forcing people to call `add_goal/s` and `evaluate_added_goals_and_make_canonical_resposne`/`try_evaluate_added_goals`
---
Other changes:
- removed the `&& false` that was introduced to the assertion in `evaluate_goal` in #108839
- remove a `!self.did_overflow()` requirement in `search_graph.is_empty()` which causes goals that overflow to ICE
- made `EvalCtxt::eq` take `&mut self` and add all the nested goals via `add_goals` instead of returning them as 99% of call sites just immediately called `EvalCtxt::add_goals` manually.
r? `````@lcnr`````
