Restrict `use_self` on nested items
Fixes#3637Fixes#3463
These changes make it so that nested items aren't visited any more by the `use_self` lint.
I think visiting nested items should be possible (so that it uses a different `item_path` for the nested item), but I'm not sure whether it's viable and what the best approach would be.
- Can `item_path` be changed to a new `Self` path before visiting the item, and then changing it back afterwards?
- Alternatively, could a new visitor be created, re-using `check_trait_method_impl_decl`?
cast_ref_to_mut lint
I see this pattern way too often, and it's completely wrong. In fact, due to how common this incorrect pattern is, [the Rustonomicon specifically points this out](https://doc.rust-lang.org/nomicon/transmutes.html).
> - Transmuting an & to &mut is UB
> - Transmuting an & to &mut is always UB
> - No you can't do it
> - No you're not special
This is my first lint.
Trigger `use_self` lint in local macros
Closes#2098
The test currently only covers local macros. #2098 suggested this:
> You could add the macro in question into the `mini_macro` subcrate
But that doesn't work for a `macro_rules`:
```
error: cannot export macro_rules! macros from a `proc-macro` crate type currently
```
So I suggest leaving out the test for external macros, as using `in_external_macro` seems straigtforward enough. Alternatives would be to use to add an additional crate (overkill if you ask me), or test with a `proc-macro`.
Integrate rustfix into Clippy test suite
Once the [PR to compiletest-rs](https://github.com/laumann/compiletest-rs/pull/151) is reviewed and merged this fixes#2376.
I will create a separate tracking issue for adding `run-rustfix` to all tests.
Only trigger `infinite_iter` lint for infinitely allocating `collect()` calls
Fixes #3538
~Oh, I guess this should actually check other methods like `count` as well, not only `collect()`.~
Never mind, `collect` is the only of these functions that allocates a data structure.
Fix if_same_then_else false positive
This fixes false positive in #3559.
The problem was that `SpanlessEq` does not check patterns in declarations. So this two blocks considered equal.
```rust
if true {
let (x, y) = foo();
} else {
let (y, x) = foo();
}
```
Not sure if the proposed change is safe as `SpanlessEq` is used extensively in other lints, but I tried hard to come up with counterexample and failed.
