Provide diagnostic suggestion in ExprUseVisitor Delegate
The [Delegate trait](981346fc07/compiler/rustc_typeck/src/expr_use_visitor.rs (L28-L38)) currently use `PlaceWithHirId` which is composed of Hir `Place` and the
corresponding expression id.
Even though this is an accurate way of expressing how a Place is used,
it can cause confusion during diagnostics.
Eg:
```
let arr : [String; 5];
let [a, ...] = arr;
^^^ E1 ^^^ = ^^E2^^
```
Here `arr` is moved because of the binding created E1. However, when we
point to E1 in diagnostics with the message `arr` was moved, it can be
confusing. Rather we would like to report E2 to the user.
Closes: https://github.com/rust-lang/project-rfc-2229/issues/20
r? `@ghost`
Add lint for 'field_reassign_with_default` #568
changelog: Add lint for field_reassign_with_default that checks if mutable object + field modification is used to edit a binding initialized with Default::default() instead of struct constructor.
Fixes#568
Notes:
- Checks for reassignment of one or more fields of a binding initialized with Default::default().
- Implemented using EarlyLintPass, might be future proofed better with LateLintPass.
- Does not trigger if Default::default() is used via another type implementing Default.
- This is a re-open of [PR#4761](https://github.com/rust-lang/rust-clippy/pull/4761), but I couldn't figure out how to re-open that one so here's a new one with the requested changes :S
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
Clarify allow/warn/deny documentation. Remove enable/disable.
Disable and enable when not specifically explained were not clear to me
as an English language speaker, but I was able to figure it out fairly
easily due to the examples having A/W, which I assumed meant `allow` and
`warn`. I removed both words to be sure it was clear as well as
extending the note on what deny means. It now includes a statement on
exactly what each word means.
Documentation only update.
*Please keep the line below*
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
The [Delegate
trait](981346fc07/compiler/rustc_typeck/src/expr_use_visitor.rs (L28-L38))
currently use `PlaceWithHirId` which is composed of Hir `Place` and the
corresponding expression id.
Even though this is an accurate way of expressing how a Place is used,
it can cause confusion during diagnostics.
Eg:
```
let arr : [String; 5];
let [a, ...] = arr;
^^^ E1 ^^^ = ^^E2^^
```
Here `arr` is moved because of the binding created E1. However, when we
point to E1 in diagnostics with the message `arr` was moved, it can be
confusing. Rather we would like to report E2 to the user.
Closes: https://github.com/rust-lang/project-rfc-2229/issues/20
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`
- Implement `field_reassign_with_default` as a `LateLintPass`
- Avoid triggering `default_trait_access` on a span already linted by
`field_reassigned_with_default`
- Merge `default_trait_access` and `field_reassign_with_default` into
`Default`
- Co-authored-by: Eduardo Broto <ebroto@tutanota.com>
- Fixes#568
