Use const sym where possible
I ran a regex search and replace to use const `sym` values where possible. This should give some performance boost by avoiding string interning at runtime.
Con: It is not as consistent as always using `sym!`.
I also changed an internal lint to suggest using `sym::{}`, making an assumption that this will always work for diagnostic items.
changelog: none
Add lint 'ref_option_ref' #1377
This lint checks for usage of `&Option<&T>` which can be simplified as `Option<&T>` as suggested in #1377.
This WIP PR is here to get feedback on the lint as there's more cases to be handled:
* statics/consts,
* associated types,
* type alias,
* function/method parameter/return,
* ADT definitions (struct/tuple struct fields, enum variants)
changelog: Add 'ref_option_ref' lint
Add lint: from_iter_instead_of_collect
Fixes#5679
This implements lint for `::from_iter()` from #5679 not the general issue (`std::ops::Add::add`, etc.).
This lint checks if expression is function call with `from_iter` name and if it's implementation of the `std::iter::FromIterator` trait.
changelog: Introduce from_iter_instead_of_collect lint
single_char_insert_str: lint using insert_str() on single-char literals and suggest insert()
Fixes#6026
changelog: add single_char_insert_str lint which lints using string.insert_str() with single char literals and suggests string.insert() with a char
Update the existing arithmetic lint
re: #6209
Updates the lint to not the error message if RHS of binary operation `/` of `%` is a literal/constant that is not `0` or `-1`, as suggested [here](https://github.com/rust-lang/rust-clippy/issues/6209#issuecomment-715624354)
changelog: Expand [`integer_arithmetic`] to work with RHS literals and constants
fix the error-causing suggestion of 'borrowed_box'
Fixes#3128
Fix the suggestion of 'borrowed_box', which causes a syntax error because it misses necessary parentheses.
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changelog: Fix the error-causing suggestion of 'borrowed_box'
Add lint for comparing to empty slices instead of using .is_empty()
Hey first time making a clippy lint
I added the implementation of the lint the `len_zero` since it shared a lot of the code, I would otherwise have to rewrite. Just tell me if the lint should use it's own file instead
changelog: Add lint for comparing to empty slices
Fixes#6217
Lint items after statements in local macro expansions
The items_after_statements lint was skipping all expansions. Instead
we should still lint local macros.
Fixes#578
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*Please keep the line below*
changelog: The items_after_statements now applies to local macro expansions
No lint in macro for `toplevel_ref_arg`
Do not lint when the span is from a macro.
Question: shouldn't we extend this for external macros also ?
Fixes: #5849
changelog: none
