Suggest changing `iter`/`into_iter` when the other was meant
When encountering a call to `iter` that should have been `into_iter` and vice-versa, provide a structured suggestion:
```
error[E0271]: type mismatch resolving `<IntoIter<{integer}, 3> as IntoIterator>::Item == &{integer}`
--> $DIR/into_iter-when-iter-was-intended.rs:5:37
|
LL | let _a = [0, 1, 2].iter().chain([3, 4, 5].into_iter());
| ----- ^^^^^^^^^^^^^^^^^^^^^ expected `&{integer}`, found integer
| |
| required by a bound introduced by this call
|
note: the method call chain might not have had the expected associated types
--> $DIR/into_iter-when-iter-was-intended.rs:5:47
|
LL | let _a = [0, 1, 2].iter().chain([3, 4, 5].into_iter());
| --------- ^^^^^^^^^^^ `IntoIterator::Item` is `{integer}` here
| |
| this expression has type `[{integer}; 3]`
note: required by a bound in `std::iter::Iterator::chain`
--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
help: consider not consuming the `[{integer}, 3]` to construct the `Iterator`
|
LL - let _a = [0, 1, 2].iter().chain([3, 4, 5].into_iter());
LL + let _a = [0, 1, 2].iter().chain([3, 4, 5].iter());
|
```
Finish addressing the original case in rust-lang/rust#68095. Only the case of chaining a `Vec` or `[]` is left unhandled.
9ad4ae88cf