When encountering an opaque closure return type that needs to bound a
lifetime to the function's arguments, including borrows and type params,
provide appropriate suggestions that lead to working code.
Get the user from
```rust
fn foo<G, T>(g: G, dest: &mut T) -> impl FnOnce()
where
G: Get<T>
{
move || {
*dest = g.get();
}
}
```
to
```rust
fn foo<'a, G: 'a, T>(g: G, dest: &'a mut T) -> impl FnOnce() +'a
where
G: Get<T>
{
move || {
*dest = g.get();
}
}
```
multiple Return terminators are possible
@ecstatic-morse mentioned in https://github.com/rust-lang/rust/issues/72515 that multiple `Return` terminators are possible. Update the docs accordingly.
Cc @rust-lang/wg-mir-opt
mir: adjust conditional in recursion limit check
Fixes#67552.
This PR adjusts the condition used in the recursion limit check of
the monomorphization collector, from `>` to `>=`.
In #67552, the test case had infinite indirect recursion, repeating a
handful of functions (from the perspective of the monomorphization
collector): `rec` -> `identity` -> `Iterator::count` -> `Iterator::fold`
-> `Iterator::next` -> `rec`.
During this process, `resolve_associated_item` was invoked for
`Iterator::fold` (during the construction of an `Instance`), and
ICE'd due to substitutions needing inference. However, previous
iterations of this recursion would have called this function for
`Iterator::fold` - and did! - and succeeded in doing so (trivially
checkable from debug logging, `()` is present where `_` is in the substs
of the failing execution).
The expected outcome of this test case would be a recursion limit error
(which is present when the `identity` fn indirection is removed), and
the recursion depth of `rec` is increasing (other functions finish
collecting their neighbours and thus have their recursion depths reset).
When the ICE occurs, the recursion depth of `rec` is 256 (which matches
the recursion limit), which suggests perhaps that a different part of
the compiler is using a `>=` comparison and returning a different result
on this recursion rather than what it returned in every previous
recursion, thus stopping the monomorphization collector from reporting
an error on the next recursion, where `recursion_depth_of_rec > 256`
would have been true.
With grep and some educated guesses, we can determine that
the recursion limit check at line 818 in
`src/librustc_trait_selection/traits/project.rs` is the other check that
is using a different comparison. Modifying either comparison to be `>` or
`>=` respectively will fix the error, but changing the monomorphization
collector produces the nicer error.
Override Box::<[T]>::clone_from
Avoid dropping and reallocating when cloning to an existing box if the lengths are the same.
It would be nice if this could also be specialized for `Copy` but I don't know how that works since it's not on stable. Will gladly look into it if it's deemed as a good idea.
This is my first PR with code, hope I did everything right 😄
Fix ICE with explicit late-bound lifetimes
Rather than returning an explicit late-bound lifetime as a generic argument count mismatch (which is not necessarily true), this PR propagates the presence of explicit late-bound lifetimes.
This avoids an ICE that can occur due to the presence of explicit late-bound lifetimes when building generic substitutions by explicitly ignoring them.
r? @varkor
cc @davidtwco (this removes a check you introduced in #60892)
Resolves#72278
Resolve overflow behavior for RangeFrom
This specifies a documented unspecified implementation detail of `RangeFrom` and makes it consistently implement the specified behavior.
Specifically, `(u8::MAX).next()` is defined to cause an overflow, and resolve that overflow in the same manner as the `Step::forward` implementation.
The inconsistency that has existed is `<RangeFrom as Iterator>::nth`. The existing behavior should be plain to see after #69659: the skipping part previously always panicked if it caused an overflow, but the final step (to set up the state for further iteration) has always been debug-checked.
The inconsistency, then, is that `RangeFrom::nth` does not implement the same behavior as the naive (and default) implementation of just calling `next` multiple times. This PR aligns `RangeFrom::nth` to have identical behavior to the naive implementation. It also lines up with the standard behavior of primitive math in Rust everywhere else in the language: debug checked overflow.
cc @Amanieu
---
Followup to #69659. Closes#25708 (by documenting the panic as intended).
The documentation wording is preliminary and can probably be improved.
This will probably need an FCP, as it changes observable stable behavior.
Rollup of 10 pull requests
Successful merges:
- #72033 (Update RELEASES.md for 1.44.0)
- #72162 (Add Extend::{extend_one,extend_reserve})
- #72419 (Miri read_discriminant: return a scalar instead of raw underlying bytes)
- #72621 (Don't bail out of trait selection when predicate references an error)
- #72677 (Fix diagnostics for `@ ..` binding pattern in tuples and tuple structs)
- #72710 (Add test to make sure -Wunused-crate-dependencies works with tests)
- #72724 (Revert recursive `TokenKind::Interpolated` expansion for now)
- #72741 (Remove unused mut from long-linker-command-lines test)
- #72750 (Remove remaining calls to `as_local_node_id`)
- #72752 (remove mk_bool)
Failed merges:
r? @ghost
Such splits arise from metadata refs into libstd.
This way, we can (in a follow on commit) continue to emit the virtual name into
things like the like the StableSourceFileId that ends up in incremetnal build
artifacts, while still using the devirtualized file path when we want to access
the file.
Note that this commit is intended to be a refactoring; the actual fix to the bug
in question is in a follow-on commit.
Fix diagnostics for `@ ..` binding pattern in tuples and tuple structs
Fixes#72574
Associated https://github.com/rust-lang/rust/pull/72534https://github.com/rust-lang/rust/issues/72373
Includes a new suggestion with `Applicability::MaybeIncorrect` confidence level.
### Before
#### tuple
```
error: `..` patterns are not allowed here
--> src/main.rs:4:19
|
4 | (_a, _x @ ..) => {}
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns
error[E0308]: mismatched types
--> src/main.rs:4:9
|
3 | match x {
| - this expression has type `({integer}, {integer}, {integer})`
4 | (_a, _x @ ..) => {}
| ^^^^^^^^^^^^^ expected a tuple with 3 elements, found one with 2 elements
|
= note: expected tuple `({integer}, {integer}, {integer})`
found tuple `(_, _)`
error: aborting due to 2 previous errors
```
#### tuple struct
```
error: `..` patterns are not allowed here
--> src/main.rs:6:25
|
6 | Binder(_a, _x @ ..) => {}
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns
error[E0023]: this pattern has 2 fields, but the corresponding tuple struct has 3 fields
--> src/main.rs:6:9
|
1 | struct Binder(i32, i32, i32);
| ----------------------------- tuple struct defined here
...
6 | Binder(_a, _x @ ..) => {}
| ^^^^^^^^^^^^^^^^^^^ expected 3 fields, found 2
error: aborting due to 2 previous errors
```
### After
*Note: final output edited during source review discussion, see thread for details*
#### tuple
```
error: `_x @` is not allowed in a tuple
--> src/main.rs:4:14
|
4 | (_a, _x @ ..) => {}
| ^^^^^^^ is only allowed in a slice
|
help: replace with `..` or use a different valid pattern
|
4 | (_a, ..) => {}
| ^^
error[E0308]: mismatched types
--> src/main.rs:4:9
|
3 | match x {
| - this expression has type `({integer}, {integer}, {integer})`
4 | (_a, _x @ ..) => {}
| ^^^^^^^^^^^^^ expected a tuple with 3 elements, found one with 1 element
|
= note: expected tuple `({integer}, {integer}, {integer})`
found tuple `(_,)`
error: aborting due to 2 previous errors
```
#### tuple struct
```
error: `_x @` is not allowed in a tuple struct
--> src/main.rs:6:20
|
6 | Binder(_a, _x @ ..) => {}
| ^^^^^^^ is only allowed in a slice
|
help: replace with `..` or use a different valid pattern
|
6 | Binder(_a, ..) => {}
| ^^
error[E0023]: this pattern has 1 field, but the corresponding tuple struct has 3 fields
--> src/main.rs:6:9
|
1 | struct Binder(i32, i32, i32);
| ----------------------------- tuple struct defined here
...
6 | Binder(_a, _x @ ..) => {}
| ^^^^^^^^^^^^^^^^^^^ expected 3 fields, found 1
error: aborting due to 2 previous errors
```
r? @estebank
Don't bail out of trait selection when predicate references an error
Fixes#72590
With PR #70551, observing a `ty::Error` guarantees that compilation is
going to fail. Therefore, there are no soundness impliciations to
continuing on when we encounter a `ty::Error` - we can only affect
whether or not additional error messags are emitted.
By not bailing out, we avoid incorrectly determining that types are
`!Sized` when a type error is present, which allows us to avoid emitting
additional spurious error messages.
The original comment mentioned this code being shared by coherence -
howver, this change resulted in no diagnostic changes in any of the
existing tests.
Add Extend::{extend_one,extend_reserve}
This adds new optional methods on `Extend`: `extend_one` add a single
element to the collection, and `extend_reserve` pre-allocates space for
the predicted number of incoming elements. These are used in `Iterator`
for `partition` and `unzip` as they shuffle elements one-at-a-time into
their respective collections.
This adds new optional methods on `Extend`: `extend_one` add a single
element to the collection, and `extend_reserve` pre-allocates space for
the predicted number of incoming elements. These are used in `Iterator`
for `partition` and `unzip` as they shuffle elements one-at-a-time into
their respective collections.
