new lint: mutable_key_type
This fixes#732 - well, partly, it doesn't adress `Hash` impls, but the use of mutable types as map keys or set members
changelog: add `mutable_key_type` lint
r? @flip1995
Add `let_underscore_must_use` lint
changelog: closes#4812 , added a new `let_underscore_must_use` lint, moved `is_must_use_ty` to utils, added `is_must_use_fn` util function
Fix `map_clone` false positive
Don't lint when the item type is not a reference. `copied` only applies to references.
changelog: Fix `map_clone` false positive
Currently the cognitive complexity lint spans the entire function
body making it really difficult to read and refactor the code in
editors. To fix this we reduce the lint span to the function name.
Move `iterator_step_by_zero` and correct the documentation
Move `iterator_step_by_zero` and correct the documentation.
changelog: Corrected `iterator_step_by_zero` documentation
Currently `cmp_nan` lint doesn't detect comparisons with NaN's
if the operands are consts variables so to fix this we evaluate
the const variables first before testing for NaN.
Fix false positive with cast_sign_loss lint
`cast_sign_loss` lint incorrectly suggests that the result of `checked_abs`, `rem_euclid` and `checked_rem_euclid` cannot be casted to an unsigned integer without loss.
Fixes#4818#4764#4743
changelog: Fix false positives in `cast_sign_loss` lint
The Rust Book recommends that functions that return a `Result` type have
a doc comment with an `# Errors` section describing the kind of errors
that can be returned
(https://doc.rust-lang.org/book/ch14-02-publishing-to-crates-io.html#commonly-used-sections).
This change adds a lint to enforce this. The lint is allow by default;
it can be enabled with `#![warn(clippy::missing_errors_doc)]`.
Closes#4854.
`cast_sign_loss` lint incorrectly suggests that the result of
`checked_abs`, `rem_euclid` and `checked_rem_euclid` cannot
be casted to an unsigned integer without loss.
Fix FP in manual_swap lint with slice-like types
Fixes#4853
changelog: Fix FP in [`manual_swap`] lint with slice-like types and make it auto applicable
