the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.
Handle infer vars in anon consts on stable
Fixes#132955
Diagnostics will sometimes try to replace generic parameters with inference variables in failing goals. This means that if we have some failing goal with an array repeat expr count anon const in it, we will wind up with some `ty::ConstKind::Unevaluated(anon_const_def, [?x])` during diagnostics which will then ICE if we do not handle inference variables correctly on stable when normalizing type system consts.
r? ```@compiler-errors```
Make precise capturing suggestion machine-applicable only if it has no APITs
cc https://github.com/rust-lang/rust/issues/132932
The only case where this suggestion is not machine-applicable is when we suggest turning arg-position impl trait into type parameters, which may expose type parameters that were not turbofishable before.
Get rid of `check_opaque_type_well_formed`
Instead, replicate it by improving the span of the opaque in `check_opaque_meets_bounds`.
This has two consequences:
1. We now prefer "concrete type differs" errors, since we'll hit those first before we check the opaque is WF.
2. Spans have gotten slightly worse.
Specifically, (2.) could be improved by adding a new obligation cause that explains that the definition's environment has stronger assumptions than the declaration.
r? lcnr
Tweak detection of multiple crate versions to be more encompassing
Previously, we only emitted the additional context if the type was in the same crate as the trait that appeared multiple times in the dependency tree. Now, we look at all traits looking for two with the same name in different crates with the same crate number, and we are more flexible looking for the types involved. This will work even if the type that implements the wrong trait version is from a different crate entirely.
```
error[E0277]: the trait bound `CustomErrorHandler: ErrorHandler` is not satisfied because the trait comes from a different crate version
--> src/main.rs:5:17
|
5 | cnb_runtime(CustomErrorHandler {});
| ^^^^^^^^^^^^^^^^^^^^^ the trait `ErrorHandler` is not implemented for `CustomErrorHandler`
|
note: there are multiple different versions of crate `c` in the dependency graph
--> /home/gh-estebank/testcase-rustc-crate-version-mismatch/c-v0.2/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ^^^^^^^^^^^^^^^^^^^^^^ this is the required trait
|
::: src/main.rs:1:5
|
1 | use b::CustomErrorHandler;
| - one version of crate `c` is used here, as a dependency of crate `b`
2 | use c::cnb_runtime;
| - one version of crate `c` is used here, as a direct dependency of the current crate
|
::: /home/gh-estebank/testcase-rustc-crate-version-mismatch/b/src/lib.rs:1:1
|
1 | pub struct CustomErrorHandler {}
| ----------------------------- this type doesn't implement the required trait
|
::: /home/gh-estebank/testcase-rustc-crate-version-mismatch/c-v0.1/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ---------------------- this is the found trait
= note: two types coming from two different versions of the same crate are different types even if they look the same
= help: you can use `cargo tree` to explore your dependency tree
```
Fix#89143.
```
error[E0277]: the trait bound `dep_2_reexport::Type: Trait` is not satisfied because the trait comes from a different crate version
--> multiple-dep-versions.rs:7:18
|
7 | do_something(Type);
| ^^^^ the trait `Trait` is not implemented for `dep_2_reexport::Type`
|
note: there are multiple different versions of crate `dependency` in the dependency graph
--> /home/gh-estebank/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-1.rs:4:1
|
3 | pub struct Type(pub i32);
| --------------- this type implements the required trait
4 | pub trait Trait {
| ^^^^^^^^^^^^^^^ this is the required trait
|
::: multiple-dep-versions.rs:1:1
|
1 | extern crate dep_2_reexport;
| ---------------------------- one version of crate `dependency` is used here, as a dependency of crate `foo`
2 | extern crate dependency;
| ------------------------ one version of crate `dependency` is used here, as a direct dependency of the current crate
|
::: /home/gh-estebank/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-2.rs:3:1
|
3 | pub struct Type;
| --------------- this type doesn't implement the required trait
4 | pub trait Trait {
| --------------- this is the found trait
= note: two types coming from two different versions of the same crate are different types even if they look the same
= help: you can use `cargo tree` to explore your dependency tree
```
The approach to accomplish this is a HACK, and we'd want a better way to do this. I believe that moving E0277 to be a structured diagnostic would help in that regard.
```
error[E0277]: the trait bound `dep_2_reexport::Type: Trait` is not satisfied because the trait comes from a different crate version
--> multiple-dep-versions.rs:7:18
|
7 | do_something(Type);
| ^^^^ the trait `Trait` is not implemented for `dep_2_reexport::Type`
|
note: there are multiple different versions of crate `dependency` in the dependency graph
--> /home/gh-estebank/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-1.rs:4:1
|
3 | pub struct Type(pub i32);
| --------------- this type implements the required trait
4 | pub trait Trait {
| ^^^^^^^^^^^^^^^ this is the required trait
|
::: multiple-dep-versions.rs:1:1
|
1 | extern crate dep_2_reexport;
| ---------------------------- one version of crate `dependency` is used here, as a dependency of crate `foo`
2 | extern crate dependency;
| ------------------------ one version of crate `dependency` is used here, as a direct dependency of the current crate
|
::: /home/gh-estebank/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-2.rs:3:1
|
3 | pub struct Type;
| --------------- this type doesn't implement the required trait
4 | pub trait Trait {
| --------------- this is the found trait
= note: two types coming from two different versions of the same crate are different types even if they look the same
= help: you can use `cargo tree` to explore your dependency tree
note: required by a bound in `do_something`
--> /home/gh-estebank/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-1.rs:12:24
|
12 | pub fn do_something<X: Trait>(_: X) {}
| ^^^^^ required by this bound in `do_something`
```
Previously, we only emitted the additional context if the type was in the same crate as the trait that appeared multiple times in the dependency tree. Now, we look at all traits looking for two with the same name in different crates with the same crate number, and we are more flexible looking for the types involved. This will work even if the type that implements the wrong trait version is from a different crate entirely.
```
error[E0277]: the trait bound `CustomErrorHandler: ErrorHandler` is not satisfied
--> src/main.rs:5:17
|
5 | cnb_runtime(CustomErrorHandler {});
| ----------- ^^^^^^^^^^^^^^^^^^^^^ the trait `ErrorHandler` is not implemented for `CustomErrorHandler`
| |
| required by a bound introduced by this call
|
help: you have multiple different versions of crate `c` in your dependency graph
--> src/main.rs:1:5
|
1 | use b::CustomErrorHandler;
| ^ one version of crate `c` is used here, as a dependency of crate `b`
2 | use c::cnb_runtime;
| ^ one version of crate `c` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
--> /home/gh-estebank/testcase-rustc-crate-version-mismatch/c-v0.2/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ^^^^^^^^^^^^^^^^^^^^^^ this is the required trait
|
::: /home/gh-estebank/testcase-rustc-crate-version-mismatch/b/src/lib.rs:1:1
|
1 | pub struct CustomErrorHandler {}
| ----------------------------- this type doesn't implement the required trait
|
::: /home/gh-estebank/testcase-rustc-crate-version-mismatch/c-v0.1/src/lib.rs:1:1
|
1 | pub trait ErrorHandler {}
| ---------------------- this is the found trait
= help: you can use `cargo tree` to explore your dependency tree
note: required by a bound in `cnb_runtime`
--> /home/gh-estebank/testcase-rustc-crate-version-mismatch/c-v0.2/src/lib.rs:3:41
|
3 | pub fn cnb_runtime(_error_handler: impl ErrorHandler) {}
| ^^^^^^^^^^^^ required by this bound in `cnb_runtime`
```
Fix#89143.
Only disable cache if predicate has opaques within it
This is an alternative to https://github.com/rust-lang/rust/pull/132075.
This refines the check implemented in https://github.com/rust-lang/rust/pull/126024 to only disable the global cache if the predicate being considered has opaques in it. This is still theoretically unsound, since goals can indirectly rely on opaques in the defining scope, but we're much less likely to hit it.
It doesn't totally fix https://github.com/rust-lang/rust/issues/132064: for example, `lemmy` goes from 1:29 (on rust 1.81) to 9:53 (on nightly) to 4:07 (after this PR). But I think it's at least *more* sound than a total revert :/
r? lcnr
Remove unnecessary pub enum glob-imports from `rustc_middle::ty`
We used to have an idiom in the compiler where we'd prefix or suffix all the variants of an enum, for example `BoundRegionKind`, with something like `Br`, and then *glob-import* that enum variant directly.
`@noratrieb` brought this up, and I think that it's easier to read when we just use the normal style `EnumName::Variant`.
This PR is a bit large, but it's just naming.
The only somewhat opinionated change that this PR does is rename `BorrowKind::Imm` to `BorrowKind::Immutable` and same for the other variants. I think these enums are used sparingly enough that the extra length is fine.
r? `@noratrieb` or reassign
Suggest creating unary tuples when types don't match a trait
When you want to have a variadic function, a common workaround to implement this is to create a trait and then implement that trait for various tuples. For example in `pyo3` there exists
```rust
/// Calls the object with only positional arguments.
pub fn call1(&self, args: impl IntoPy<Py<PyTuple>>) -> PyResult<&PyAny> {
...
}
```
with various impls like
```rust
impl<A: IntoPy<PyObject> IntoPy<Py<PyAny>> for (A,)
impl<A: IntoPy<PyObject, B: IntoPy<PyObject> IntoPy<Py<PyAny>> for (A, B)
... etc
```
This means that if you want to call the method with a single item you have to create a unary tuple, like `(x,)`, rather than just `x`.
This PR implements a suggestion to do that, if applicable.
Do not suggest `#[derive(Copy)]` when we wanted a `!Copy` type.
Do not say "`Copy` is not implemented for `T` but `Copy` is".
Do not talk about `Trait` having no implementations when `!Trait` was desired.
```
error[E0277]: the trait bound `{gen block@$DIR/gen_block_is_coro.rs:7:5: 7:8}: Coroutine` is not satisfied
--> $DIR/gen_block_is_coro.rs:6:13
|
LL | fn foo() -> impl Coroutine<Yield = u32, Return = ()> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Coroutine` is not implemented for `{gen block@$DIR/gen_block_is_coro.rs:7:5: 7:8}`
LL | gen { yield 42 }
| ---------------- return type was inferred to be `{gen block@$DIR/gen_block_is_coro.rs:7:5: 7:8}` here
```
The secondary span label is new.
When a trait is not implemented for a type, but there *is* an `impl`
for another type or different trait params, we format the output to
use highlighting in the same way that E0308 does for types.
The logic accounts for 3 cases:
- When both the type and trait in the expected predicate and the candidate are different
- When only the types are different
- When only the trait generic params are different
For each case, we use slightly different formatting and wording.
continue `TypingMode` refactor
There are still quite a few places which (indirectly) rely on the `Reveal` of a `ParamEnv`, but we're slowly getting there
r? `@compiler-errors`
Remove region from adjustments
It's not necessary to store this region, because it's only used in THIR and MemCat/ExprUse, both of which already basically only deal with erased regions anyways.
Try to point out when edition 2024 lifetime capture rules cause borrowck issues
Lifetime capture rules in 2024 are modified to capture more lifetimes, which sometimes lead to some non-local borrowck errors. This PR attempts to link these back together with a useful note pointing out the capture rule changes.
This is not a blocking concern, but I'd appreciate feedback (though, again, I'd like to stress that I don't want to block this PR on this): I'm worried about this note drowning in the sea of other diagnostics that borrowck emits. I was tempted to change the level of the note to `.span_warn` just so it would show up in a different color. Thoughts?
Fixes#130545
Opening as a draft first since it's stacked on #131183.
r? `@ghost`
