Rollup of 5 pull requests #71012
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Rollup of 5 pull requests #71012
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The `_` binding form is special, in that it encodes a "no-op": nothing is actually bound, and thus nothing is moved or borrowed in this scenario. Usually we do the "right" thing in all such cases. The exceptions are explicitly pointed out in this test case, so that we keep track of whether they are eventually fixed.
Co-Authored-By: Mazdak Farrokhzad <twingoow@gmail.com>
Co-Authored-By: Mazdak Farrokhzad <twingoow@gmail.com>
…entril tests encoding current behavior for various cases of "binding" to _. The `_` binding form is special, in that it encodes a "no-op": nothing is actually bound, and thus nothing is moved or borrowed in this scenario. Usually we do the "right" thing in all such cases. The exceptions are explicitly pointed out in this test case, so that we keep track of whether they are eventually fixed. Cc rust-lang#53114. (This does not close the aforementioned issue; it just adds the tests encoding the current behavior, which we hope to eventually fix.)
… r=Centril
Handle `impl Trait` where `Trait` has an assoc type with missing bounds
When encountering a type parameter that needs more bounds the trivial case is `T` `where T: Bound`, but it can also be an `impl Trait` param that needs to be decomposed to a type param for cleaner code. For example, given
```rust
fn foo(constraints: impl Iterator) {
for constraint in constraints {
println!("{:?}", constraint);
}
}
```
the previous output was
```
error[E0277]: `<impl Iterator as std::iter::Iterator>::Item` doesn't implement `std::fmt::Debug`
--> src/main.rs:3:26
|
1 | fn foo(constraints: impl Iterator) {
| - help: consider further restricting the associated type: `where <impl Iterator as std::iter::Iterator>::Item: std::fmt::Debug`
2 | for constraint in constraints {
3 | println!("{:?}", constraint);
| ^^^^^^^^^^ `<impl Iterator as std::iter::Iterator>::Item` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
|
= help: the trait `std::fmt::Debug` is not implemented for `<impl Iterator as std::iter::Iterator>::Item`
= note: required by `std::fmt::Debug::fmt`
```
which is incorrect as `where <impl Iterator as std::iter::Iterator>::Item: std::fmt::Debug` is not valid syntax nor would it restrict the positional `impl Iterator` parameter if it were.
The output being introduced is
```
error[E0277]: `<impl Iterator as std::iter::Iterator>::Item` doesn't implement `std::fmt::Debug`
--> src/main.rs:3:26
|
3 | println!("{:?}", constraint);
| ^^^^^^^^^^ `<impl Iterator as std::iter::Iterator>::Item` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
|
= help: the trait `std::fmt::Debug` is not implemented for `<impl Iterator as std::iter::Iterator>::Item`
= note: required by `std::fmt::Debug::fmt`
help: introduce a type parameter with a trait bound instead of using `impl Trait`
|
LL | fn foo<T: Iterator>(constraints: T) where <T as std::iter::Iterator>::Item: std::fmt::Debug {
| ^^^^^^^^^^^^^ ^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
This suggestion is correct and lead the user in the right direction: because you have an associated type restriction you can no longer use `impl Trait`, the only reasonable alternative is to introduce a named type parameter, bound by `Trait` and with a `where` binding on the associated type for the new type parameter `as Trait` for the missing bound.
*Ideally*, we would want to suggest something like the following, but that is not valid syntax today
```
error[E0277]: `<impl Iterator as std::iter::Iterator>::Item` doesn't implement `std::fmt::Debug`
--> src/main.rs:3:26
|
3 | println!("{:?}", constraint);
| ^^^^^^^^^^ `<impl Iterator as std::iter::Iterator>::Item` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
|
= help: the trait `std::fmt::Debug` is not implemented for `<impl Iterator as std::iter::Iterator>::Item`
= note: required by `std::fmt::Debug::fmt`
help: introduce a type parameter with a trait bound instead of using `impl Trait`
|
LL | fn foo(constraints: impl Iterator<Item: std::fmt::Debug>) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
Fix rust-lang#69638.
…, r=matthewjasper Normalize MIR locals' types for generator layout computation. fixes rust-lang#70905
…fJung added machine hooks to track deallocations This is part of rust-lang/miri#1314 in order to allow miri to show stack traces for on deallocation in order to debug use-after-free bugs
Normalize function signature in function casting check procedure Fixes rust-lang#54094 ```rust trait Zoo { type X; } impl Zoo for u16 { type X = usize; } fn foo(abc: <u16 as Zoo>::X) {} fn main() { let x: *const u8 = foo as _; } ``` Currently a `FnDef` need to be checked if it's able to cast to `FnPtr` before it is actually casted. But the signature of `FnPtr` target's associated types are not normalized: https://github.com/rust-lang/rust/blob/96d77f0e5f103612d62b85938aacfb33f5768433/src/librustc_typeck/check/cast.rs#L536-L553 However, during the coercion check, the signature of `FnPtr` target's associated types are normalized (The `<u16 as Zoo>::X` turns into `usize`). https://github.com/rust-lang/rust/blob/96d77f0e5f103612d62b85938aacfb33f5768433/src/librustc_typeck/check/coercion.rs#L687-L729 This inconsistency leads to the error:`Err(Sorts(ExpectedFound { expected: <u16 as Zoo>::X, found: usize }))`.
|
@bors r+ rollup=never p=5 |
|
📌 Commit 2af0b16 has been approved by |
bors
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|
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Successful merges:
impl TraitwhereTraithas an assoc type with missing bounds #69707 (Handleimpl TraitwhereTraithas an assoc type with missing bounds)Failed merges:
r? @ghost