impl `Default` for collection iterators that don't already have it
There is a pretty strong precedent for implementing `Default` for collection iterators, and this does so for some where this implementation was missed.
I don't think this needs a separate ACP (since this precedent already exists, and these feel like they were just missed), however, it *will* need an FCP since these implementations are instantly stable.
Update tracking issue for `const_binary_heap_new_in`
This PR updates the tracking issue of `const_binary_heap_new_in` feature:
- Old issue: #112353
- New issue: #125961
Specifically, when an override doesn't just forward to an inner type,
document the behavior and that it's preferred over simply assigning
a clone of source. Also, change instances where the second parameter is
"other" to "source".
Help with common API confusion, like asking for `push` when the data structure really has `append`.
```
error[E0599]: no method named `size` found for struct `Vec<{integer}>` in the current scope
--> $DIR/rustc_confusables_std_cases.rs:17:7
|
LL | x.size();
| ^^^^
|
help: you might have meant to use `len`
|
LL | x.len();
| ~~~
help: there is a method with a similar name
|
LL | x.resize();
| ~~~~~~
```
#59450
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
Expand in-place iteration specialization to Flatten, FlatMap and ArrayChunks
This enables the following cases to collect in-place:
```rust
let v = vec![[0u8; 4]; 1024]
let v: Vec<_> = v.into_iter().flatten().collect();
let v: Vec<Option<NonZeroUsize>> = vec![NonZeroUsize::new(0); 1024];
let v: Vec<_> = v.into_iter().flatten().collect();
let v = vec![u8; 4096];
let v: Vec<_> = v.into_iter().array_chunks::<4>().collect();
```
Especially the nicheful-option-flattening should be useful in real code.
Ignore `core`, `alloc` and `test` tests that require unwinding on `-C panic=abort`
Some of the tests for `core` and `alloc` require unwinding through their use of `catch_unwind`. These tests fail when testing using `-C panic=abort` (in my case through a target without unwinding support, and `-Z panic-abort-tests`), while they should be ignored as they don't indicate a failure.
This PR marks all of these tests with this attribute:
```rust
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
```
I'm not aware of a way to test this on rust-lang/rust's CI, as we don't test any target with `-C panic=abort`, but I tested this locally on a Ferrocene target and it does indeed make the test suite pass.
binary_heap: Optimize Extend implementation.
This PR makes the `Extend` implementation for `BinaryHeap` no longer rely on specialization, so that it always use the bulk rebuild optimization that was previously only available for the `Vec` specialization.
Previously the bulk rebuild specialization was only available with Vec, and
for general iterators Extend only provided pre-allocation through reserve().
By using a drop guard, we can safely bulk rebuild even if the iterator may
panic. This allows benefiting from the bulk rebuild optimization without
collecting iterator elements into a Vec beforehand, which would nullify any
performance gains from bulk rebuild.
Test leaking of BinaryHeap Drain iterators
Add test cases about forgetting the `BinaryHeap::Drain` iterator, and slightly fortifies some other test cases.
Consists of separate commits that I don't think are relevant on their own (but I'll happily turn these into more PRs if desired).
