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
Implement rustc side of report-future-incompat
cc https://github.com/rust-lang/rust/issues/71249
This is an alternative to `@pnkfelix's` initial implementation in https://github.com/pnkfelix/rust/commits/prototype-rustc-side-of-report-future-incompat (mainly because I started working before seeing that branch 😄 ).
My approach outputs the entire original `Diagnostic`, in a way that is compatible with incremental compilation. This is not yet integrated with compiletest, but can be used manually by passing `-Z emit-future-incompat-report` to `rustc`.
Several changes are made to support this feature:
* The `librustc_session/lint` module is moved to a new crate `librustc_lint_defs` (name bikesheddable). This allows accessing lint definitions from `librustc_errors`.
* The `Lint` struct is extended with an `Option<FutureBreakage>`. When present, it indicates that we should display a lint in the future-compat report. `FutureBreakage` contains additional information that we may want to display in the report (currently, a `date` field indicating when the crate will stop compiling).
* A new variant `rustc_error::Level::Allow` is added. This is used when constructing a diagnostic for a future-breakage lint that is marked as allowed (via `#[allow]` or `--cap-lints`). This allows us to capture any future-breakage diagnostics in one place, while still discarding them before they are passed to the `Emitter`.
* `DiagnosticId::Lint` is extended with a `has_future_breakage` field, indicating whether or not the `Lint` has future breakage information (and should therefore show up in the report).
* `Session` is given access to the `LintStore` via a new `SessionLintStore` trait (since `librustc_session` cannot directly reference `LintStore` without a cyclic dependency). We use this to turn a string `DiagnosticId::Lint` back into a `Lint`, to retrieve the `FutureBreakage` data.
Currently, `FutureBreakage.date` is always set to `None`. However, this could potentially be interpreted by Cargo in the future.
I've enabled the future-breakage report for the `ARRAY_INTO_ITER` lint, which can be used to test out this PR. The intent is to use the field to allow Cargo to determine the date of future breakage (as described in [RFC 2834](https://github.com/rust-lang/rfcs/blob/master/text/2834-cargo-report-future-incompat.md)) without needing to parse the diagnostic itself.
cc `@pnkfelix`
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
