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`
Rename `rustc_abi::Abi` to `BackendRepr`
Remove the confabulation of `rustc_abi::Abi` with what "ABI" actually means by renaming it to `BackendRepr`, and rename `Abi::Aggregate` to `BackendRepr::Memory`. The type never actually represented how things are passed, as that has to have `PassMode` considered, at minimum, but rather it just is how we represented some things to the backend. This conflation arose because LLVM, the primary backend at the time, would lower certain IR forms using certain ABIs. Even that only somewhat was true, as it broke down when one ventured significantly afield of what is described by the System V AMD64 ABI either by using different architectures, ABI-modifying IR annotations, the same architecture **with different ISA extensions enabled**, or other... unexpected delights.
Unfortunately both names are still somewhat of a misnomer right now, as people have written code for years based on this misunderstanding. Still, their original names are even moreso, and for better or worse, this backend code hasn't received as much maintenance as the rest of the compiler, lately. Actually arriving at a correct end-state will simply require us to disentangle a lot of code in order to fix, much of it pointlessly repeated in several places. Thus this is not an "actual fix", just a way to deflect further misunderstandings.
TypingMode: merge intercrate, reveal, and defining_opaque_types
This adds `TypingMode` and uses it in most places. We do not yet remove `Reveal` from `param_env`s. This and other future work as tracked in #132279 and via `FIXME`s.
Fetching the `TypingMode` of the `InferCtxt` asserts that the `TypingMode` agrees with `ParamEnv::reveal` to make sure we don't introduce any subtle bugs here. This will be unnecessary once `ParamEnv::reveal` no longer exists.
As the `TypingMode` is now a part of the query input, I've merged the coherence and non-coherence caches for the new solver. I've also enabled the local `infcx` cache during coherence by clearing the cache when forking it with a different `TypingMode`.
#### `TypingMode::from_param_env`
I am using this even in cases where I know that the `param_env` will always be `Reveal::UserFacing`. This is to make it easier to correctly refactor this code in the future, any time we use `Reveal::UserFacing` in a body while not defining its opaque types is incorrect and should use a `TypingMode` which only reveals opaques defined by that body instead, cc #124598
r? ``@compiler-errors``
The initial naming of "Abi" was an awful mistake, conveying wrong ideas
about how psABIs worked and even more about what the enum meant.
It was only meant to represent the way the value would be described to
a codegen backend as it was lowered to that intermediate representation.
It was never meant to mean anything about the actual psABI handling!
The conflation is because LLVM typically will associate a certain form
with a certain ABI, but even that does not hold when the special cases
that actually exist arise, plus the IR annotations that modify the ABI.
Reframe `rustc_abi::Abi` as the `BackendRepr` of the type, and rename
`BackendRepr::Aggregate` as `BackendRepr::Memory`. Unfortunately, due to
the persistent misunderstandings, this too is now incorrect:
- Scattered ABI-relevant code is entangled with BackendRepr
- We do not always pre-compute a correct BackendRepr that reflects how
we "actually" want this value to be handled, so we leave the backend
interface to also inject various special-cases here
- In some cases `BackendRepr::Memory` is a "real" aggregate, but in
others it is in fact using memory, and in some cases it is a scalar!
Our rustc-to-backend lowering code handles this sort of thing right now.
That will eventually be addressed by lifting duplicated lowering code
to either rustc_codegen_ssa or rustc_target as appropriate.
Remove the "which is required by `{root_obligation}`" post-script in
"the trait `X` is not implemented for `Y`" explanation in E0277. This
information is already conveyed in the notes explaining requirements,
making it redundant while making the text (particularly in labels)
harder to read.
```
error[E0277]: the trait bound `NotCopy: Copy` is not satisfied
--> $DIR/wf-static-type.rs:10:13
|
LL | static FOO: IsCopy<Option<NotCopy>> = IsCopy { t: None };
| ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `NotCopy`
|
= note: required for `Option<NotCopy>` to implement `Copy`
note: required by a bound in `IsCopy`
--> $DIR/wf-static-type.rs:7:17
|
LL | struct IsCopy<T:Copy> { t: T }
| ^^^^ required by this bound in `IsCopy`
```
vs the prior
```
error[E0277]: the trait bound `NotCopy: Copy` is not satisfied
--> $DIR/wf-static-type.rs:10:13
|
LL | static FOO: IsCopy<Option<NotCopy>> = IsCopy { t: None };
| ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `NotCopy`, which is required by `Option<NotCopy>: Copy`
|
= note: required for `Option<NotCopy>` to implement `Copy`
note: required by a bound in `IsCopy`
--> $DIR/wf-static-type.rs:7:17
|
LL | struct IsCopy<T:Copy> { t: T }
| ^^^^ required by this bound in `IsCopy`
```
Remove `ObligationCause::span()` method
I think it's an incredibly confusing footgun to expose both `obligation_cause.span` and `obligation_cause.span()`. Especially because `ObligationCause::span()` (the method) seems to just be hacking around a single quirk in the way we set up obligation causes for match arms.
First commit removes the need for that hack, with only one diagnostic span changing (but IMO not really getting worse -- I'd argue that it was already confusing).
