Clean up type alias impl trait implementation
- Removes special case for top-level impl trait
- Removes associated opaque types
- Forbid lifetime elision in let position impl trait. This is consistent with the behavior for inferred types.
- Handle lifetimes in type alias impl trait more uniformly with other parameters
cc #69323
cc #63063Closes#57188Closes#62988Closes#69136Closes#73061
Macro use sugg
changelog: Add auto applicable suggstion to macro_use_imports
fixes#5275
<s>Where exactly is the `wildcard_imports_helper` I haven't been able to import anything ex.
`use lazy_static;` or something like for that I get version/compiler conflicts?</s>
Found it.
Should we also check for `#[macro_use] extern crate`, although this is still depended on for stuff like `rustc_private`?
let_and_return: avoid "does not live long enough" errors
EDIT: Add #3324 to the list of fixes
<details>
<summary>Description of old impl</summary>
<br>
Avoid suggesting turning the RHS expression of the last statement into the block tail expression if a temporary borrows from a local that would be destroyed before.
This is my first incursion into MIR so there's probably room for improvement!
</details>
Avoid linting if the return type of some method or function called in the last statement has a lifetime parameter.
changelog: Fix false positive in [`let_and_return`]
Fixes#3792Fixes#3324
New lint: `unnested_or_patterns`
changelog: Adds a lint `unnested_or_patterns`, suggesting `Some(0 | 2)` as opposed to `Some(0) | Some(2)`. The lint only fires on compilers capable of using `#![feature(or_patterns)]`.
- The lint is primarily encoded as a pure algorithm which to unnest or-patterns in an `ast::Pat` (`fn unnest_or_patterns`) through a `MutVisitor`. After that is done, and assuming that any change was detected, then `pprust::pat_to_string` is used to simply convert the transformed pattern into a suggestion.
- The PR introduces a module `utils::ast_utils` with a bunch of functions for spanless & nodeless equality comparisons of ASTs.
cc https://github.com/rust-lang/rust/issues/54883
