mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-27 09:14:20 +00:00
e485a02ef2
Add `assigning_clones` lint This PR is a "revival" of https://github.com/rust-lang/rust-clippy/pull/10613 (with `@kpreid's` permission). I tried to resolve most of the unresolved things from the mentioned PR: 1) The lint now checks properly if we indeed call the functions `std::clone::Clone::clone` or `std::borrow::ToOwned::to_owned`. 2) It now supports both method and function (UFCS) calls. 3) A heuristic has been added to decide if the lint should apply. It will only apply if the type on which the method is called has a custom implementation of `clone_from/clone_into`. Notably, it will not trigger for types that use `#[derive(Clone)]`. 4) `Deref` handling has been (hopefully) a bit improved, but I'm not sure if it's ideal yet. I also added a bunch of additional tests. There are a few things that could be improved, but shouldn't be blockers: 1) When the right-hand side is a function call, it is transformed into e.g. `::std::clone::Clone::clone(...)`. It would be nice to either auto-import the `Clone` trait or use the original path and modify it (e.g. `clone::Clone::clone` -> `clone::Clone::clone_from`). I don't know how to modify the `QPath` to do that though. 2) The lint currently does not trigger when the left-hand side is a local variable without an initializer. This is overly conservative, since it could trigger when the variable has no initializer, but it has been already initialized at the moment of the function call, e.g. ```rust let mut a; ... a = Foo; ... a = b.clone(); // Here the lint should trigger, but currently doesn't ``` These cases probably won't be super common, but it would be nice to make the lint more precise. I'm not sure how to do that though, I'd need access to some dataflow analytics or something like that. changelog: new lint [`assigning_clones`] |
||
|---|---|---|
| .. | ||
| src | ||
| Cargo.toml | ||
| README.md | ||