New Lint: Manual Flatten
This is a draft PR for [Issue 6564](https://github.com/rust-lang/rust-clippy/issues/6564).
r? `@camsteffen`
- \[x] Followed [lint naming conventions][lint_naming]
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[x] Executed `cargo dev update_lints`
- \[x] Added lint documentation
- \[x] Run `cargo dev fmt`
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: Add new lint [`manual_flatten`] to check for loops over a single `if let` expression with `Result` or `Option`.
Fix let_and_return false positive
The issue:
See this Rust playground link: https://play.rust-lang.org/?edition=2018&gist=12cb5d1e7527f8c37743b87fc4a53748
Run the above with clippy to see the following warning:
```
warning: returning the result of a `let` binding from a block
--> src/main.rs:24:5
|
23 | let value = Foo::new(&x).value();
| --------------------------------- unnecessary `let` binding
24 | value
| ^^^^^
|
= note: `#[warn(clippy::let_and_return)]` on by default
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_and_return
help: return the expression directly
|
23 |
24 | Foo::new(&x).value()
|
```
Implementing the suggested fix, removing the temporary let binding,
yields a compiler error:
```
error[E0597]: `x` does not live long enough
--> src/main.rs:23:14
|
23 | Foo::new(&x).value()
| ---------^^-
| | |
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
24 | }
| -
| |
| `x` dropped here while still borrowed
| ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `Foo`
|
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
23 | let x = Foo::new(&x).value(); x
| ^^^^^^^ ^^^
```
The fix:
Of course, clippy looks like it should already handle this edge case;
however, it appears `utils::fn_def_id` is not returning a `DefId` for
`Foo::new`. Changing the `qpath_res` lookup to use the child Path
`hir_id` instead of the parent Call `hir_id` fixes the issue.
changelog: none
Do not lint when range is completely included into another one
This fix has been developed following this [comment](https://github.com/rust-lang/rust-clippy/issues/5986#issuecomment-703313548).
So this will be linted:
```
|----------|
|-----------|
```
Now this won't be linted:
```
|---|
|--------------------|
```
and this will still lint:
```
|--------|
|--------------|
```
Fixes: #5986
changelog: Fix FPs in match_overlapping_arm, when first arm is completely included in second arm
The issue:
See this Rust playground link: https://play.rust-lang.org/?edition=2018&gist=12cb5d1e7527f8c37743b87fc4a53748
Run the above with clippy to see the following warning:
```
warning: returning the result of a `let` binding from a block
--> src/main.rs:24:5
|
23 | let value = Foo::new(&x).value();
| --------------------------------- unnecessary `let` binding
24 | value
| ^^^^^
|
= note: `#[warn(clippy::let_and_return)]` on by default
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_and_return
help: return the expression directly
|
23 |
24 | Foo::new(&x).value()
|
```
Implementing the suggested fix, removing the temporary let binding,
yields a compiler error:
```
error[E0597]: `x` does not live long enough
--> src/main.rs:23:14
|
23 | Foo::new(&x).value()
| ---------^^-
| | |
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
24 | }
| -
| |
| `x` dropped here while still borrowed
| ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `Foo`
|
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
23 | let x = Foo::new(&x).value(); x
| ^^^^^^^ ^^^
```
The fix:
Of course, clippy looks like it should already handle this edge case;
however, it appears `utils::fn_def_id` is not returning a `DefId` for
`Foo::new`. Changing the `qpath_res` lookup to use the child Path
`hir_id` instead of the parent Call `hir_id` fixes the issue.
Improve safety of `LateContext::qpath_res`
This is my first rustc code change, inspired by hacking on clippy!
The first change is to clear cached `TypeckResults` from `LateContext` when visiting a nested item. I took a hint from [here](5e91c4ecc0/compiler/rustc_privacy/src/lib.rs (L1300)).
Clippy has a `qpath_res` util function to avoid a possible ICE in `LateContext::qpath_res`. But the docs of `LateContext::qpath_res` promise no ICE. So this updates the `LateContext` method to keep its promises, and removes the util function.
Related: rust-lang/rust-clippy#4545
CC ````````````@eddyb```````````` since you've done related work
CC ````````````@flip1995```````````` FYI
Make more traits of the From/Into family diagnostic items
Following traits are now diagnostic items:
- `From` (unchanged)
- `Into`
- `TryFrom`
- `TryInto`
This also adds symbols for those items:
- `into_trait`
- `try_from_trait`
- `try_into_trait`
Related: https://github.com/rust-lang/rust-clippy/pull/6620#discussion_r562482587
Refractor a few more types to `rustc_type_ir`
In the continuation of #79169, ~~blocked on that PR~~.
This PR:
- moves `IntVarValue`, `FloatVarValue`, `InferTy` (and friends) and `Variance`
- creates the `IntTy`, `UintTy` and `FloatTy` enums in `rustc_type_ir`, based on their `ast` and `chalk_ir` equilavents, and uses them for types in the rest of the compiler.
~~I will split up that commit to make this easier to review and to have a better commit history.~~
EDIT: done, I split the PR in commits of 200-ish lines each
r? `````@nikomatsakis````` cc `````@jackh726`````
Similar names ignore underscore prefixed names
changelog: Ignore underscore-prefixed names for similar_names
IMO, this lint is not very helpful for underscore-prefixed variables. Usually they are unused or are just there to ignore part of a destructuring.
`manual_filter_map` and `manual_find_map`
changelog: Add `manual_filter_map` and replace `find_map` with `manual_find_map`
Replaces #6453Fixes#3188Fixes#4193
~Depends on #6567 (to fix an internal lint false positive)~
This replaces `filter_map` and `find_map` with `manual_filter_map` and `manual_find_map` respectively. However, `filter_map` is left in place since it is used for a variety of other cases. See discussion in #6453.
Following traits are now diagnostic items:
- `From` (unchanged)
- `Into`
- `TryFrom`
- `TryInto`
This also adds symbols for those items:
- `into_trait`
- `try_from_trait`
- `try_into_trait`
Doc markdown
I added "WebGL" along the lines of the existing "OpenGL" to the whitelist of `doc_markdown` as I found this to be a pretty common term.
(this is a follow-up of the now closed https://github.com/rust-lang/rust-clippy/pull/6388)
changelog: Whitelist "WebGL" in `doc_markdown`.
Fix false positive in write_literal and print_literal (numeric literals)
changelog: No longer lint numeric literals in [`write_literal`] and [`print_literal`].
Fixes#6335
Fix the reversed suggestion message of `stable_sort_primitive`.
Now Clippy emits `stable_sort_primitive` warning as follows:
```
warning: used sort instead of sort_unstable to sort primitive type `usize`
--> src\asm.rs:41:13
|
41 | self.successors.sort();
| ^^^^^^^^^^^^^^^^^^^^^^ help: try: `self.successors.sort_unstable()`
|
= note: `#[warn(clippy::stable_sort_primitive)]` on by default
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#stable_sort_primitive
```
I think the position of `sort` and `sort_unstable` in the first line should be reversed.
changelog: Fix the reversed suggestion message of `stable_sort_primitive`.
Fixes#81007
Previously, we would fail to collect tokens in the proper place when
only builtin attributes were present. As a result, we would end up with
attribute tokens in the collected `TokenStream`, leading to duplication
when we attempted to prepend the attributes from the AST node.
We now explicitly track when token collection must be performed due to
nomterminal parsing.
Fix path_to_res for enum inherent items
changelog: none
I tried to add `Option::is_some` to the paths but got a false positive from the invalid paths lint. Turns out the `path_to_res` function does not find inherent impls for enums. I fixed this and took the liberty to do some additional cleanup in the method.
It is fairly common to divide some length in bytes by the byte-size of a
single element before creating a `from_raw_parts` slice or similar
operation. This lint would erroneously disallow such expressions.
Just in case, instead of simply disabling this lint in the RHS of a
division, keep track of the inversion and enable it again on recursive
division.
New Lint: inspect_then_for_each
**Work In Progress**
This PR addresses [Issue 5209](https://github.com/rust-lang/rust-clippy/issues/5209) and adds a new lint called `inspect_then_for_each`.
Current seek some guidance.
If you added a new lint, here's a checklist for things that will be
checked during review or continuous integration.
- \[x] Followed [lint naming conventions][lint_naming]
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[x] Executed `cargo dev update_lints`
- \[x] Added lint documentation
- \[x] Run `cargo dev fmt`
[lint_naming]: https://rust-lang.github.io/rfcs/0344-conventions-galore.html#lints
---
changelog: Add [`inspect_for_each`] lint for the use of `inspect().for_each()` on `Iterators`.
New lint: redundant_slicing
changelog: Added lint: `redundant_slicing`
fixes#6519
This will trigger on any type which implements `Index<RangeFull>` that returns the input type. This would be a false positive if the implementation does something other than return itself, but I'm not sure why you would ever want to do that.
Fix the ICE 6539
Fixes#6539
It happened because `zero_sized_map_values` used `layout_of` with types from type aliases, which is essentially the same as the ICE 4968.
---
changelog: Fix an ICE in `zero_sized_map_values`
Fix FP with empty return for `needless_return` lint
This fixes a false positive in `needless_return` lint, when triggered in a closure using `return` statement without value.
Fixes: #6501
changelog: none
Case sensitive file extensions
Closes#6425
Looks for ends_with methods calls with case sensitive extension comparisons.
changelog: Add new lint that warns about case-sensitive file extension comparisons.
Rework diagnostics for wrong number of generic args (fixes#66228 and #71924)
This PR reworks the `wrong number of {} arguments` message, so that it provides more details and contextual hints.
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
Catch `pointer::cast` too in `cast_ptr_alignment`
Fixes#4708
Although there were some discussion in the issue, this PR implements the original feature. I think `cast_ptr_alignment` should exist as it is, separated from `ptr_as_ptr`.
---
changelog: Extend `cast_ptr_alignment` lint for the `pointer::cast` method
Fix FP for `boxed_local` lint in default trait fn impl
Fix FP on default trait function implementation on `boxed_local` lint.
Maybe I checked too much when looking if `self` is carrying `Self` in its bound type.
I can't find a good test case for this, so it could be too much conservative.
Let me know if you think only detecting `self` parameter is enough.
Fixes: #4804
changelog: none
Fix derive and macro related false positives in `field_reassign_with_default`
Closes#6545
changelog: Fix derive and macro related false positives in [`field_reassign_with_default`]
Add a new lint `ptr_as_ptr`
This PR adds a new lint `ptr_as_ptr` which checks for `as` casts between raw pointers without changing its mutability and suggest replacing it with `pointer::cast`. Closes#5890.
Open question: should this lint be `pedantic` or `style`? I set it `pedantic` for now because the original post suggests using it, but I think the lint also fits well to `style`.
---
changelog: New lint `ptr_as_ptr`
Fix: Empty enum never type suggested only if the feature is enabled
This PR addresses [Issue 6422](https://github.com/rust-lang/rust-clippy/issues/6422). Instead of always recommending `never type` for empty enums, Clippy would only recommend [the lint](https://rust-lang.github.io/rust-clippy/master/index.html#empty_enum) if [LatePass.TyCtxt](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/context/struct.TyCtxt.html) has `features().never_type` enabled.
- \[ ] Followed [lint naming conventions][lint_naming]
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[x] Executed `cargo dev update_lints`
- \[x] Added lint documentation
- \[x] Run `cargo dev fmt`
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: Only trigger [`empty_enum`] lint if `never_type` feature is enabled.
New lint: vec_init_then_push
fixes: #1483
This will trigger on `new`, `default`, and `with_capacity` when the given capacity is less than or equal to the number of push calls. Is there anything else this should trigger on?
changelog: Added lint: `vec_init_then_push`
This splits up clippy::collapsible_if into collapsible_if for
if x {
if y { }
}
=>
if x && y { }
and collapsible_else_if for
if x {
} else {
if y { }
}
=>
if x {
} else if y {
}
so that we can lint for only the latter but not the first if we desire.
changelog: collapsible_if: split up linting for if x {} else { if y {} } into collapsible_else_if lint
Clippy treated Rust 2021 as Rust 2015, because 2018 was checked with
`==` instead of `>=`. This fixes that, such that 2018-specific things
are also enabled for 2021.
- Adds optional default values to const generic parameters in the AST
and HIR
- Parses these optional default values
- Adds a `const_generics_defaults` feature gate
Reassign default private
changelog: fix field_reassign_with_default false positive
* Fix#6344
* Fix assumption that `field: Default::default()` is the same as `..Default::default()`
* Cleanup some redundant logic
Added from_over_into lint
Closes#6456
Added a lint that searches for implementations of `Into<..>` and suggests to implement `From<..>` instead, as it comes with a default implementation of `Into`. Category: style.
changelog: added `from_over_into` lint
Lint also in trait def for `wrong_self_convention`
Extends `wrong_self_convention` to lint also in trait definition.
By the way, I think the `wrong_pub_self_convention` [example](dd826b4626/clippy_lints/src/methods/mod.rs (L197)) is misleading.
On [playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=32615ab3f6009e7e42cc3754be0ca17f), it fires `wrong_self_convention`, so the example (or the lint maybe?) needs to be reworked.
The difference with `wrong_self_convention` [example](dd826b4626/clippy_lints/src/methods/mod.rs (L172)) is mainly the `pub` keyword on the method `as_str`, but the lint doesn't use the function visibility as condition to choose which lint to fire (in fact it uses the visibility of the impl item).
fixes: #6307
changelog: Lint `wrong_self_convention` lint in trait def also
needless_doctest_main: handle correctly parse errors
Before this change, finding an error when parsing a doctest would make Clippy exit without emitting an error. Now we properly catch a fatal error and ignore it.
Also, if a doctest specifies an edition in the info line, it will be used when parsing it.
changelog: needless_doctest_main: handle correctly parse errors
Fixes#6022
Move binder for dyn to each list item
This essentially changes `ty::Binder<&'tcx List<ExistentialTraitRef>>` to `&'tcx List<ty::Binder<ExistentialTraitRef>>`.
This is a first step in moving the `dyn Trait` representation closer to Chalk, which we've talked about in `@rust-lang/wg-traits.`
r? `@nikomatsakis`
Implement if-let match guards
Implements rust-lang/rfcs#2294 (tracking issue: #51114).
I probably should do a few more things before this can be merged:
- [x] Add tests (added basic tests, more advanced tests could be done in the future?)
- [x] Add lint for exhaustive if-let guard (comparable to normal if-let statements)
- [x] Fix clippy
However since this is a nightly feature maybe it's fine to land this and do those steps in follow-up PRs.
Thanks a lot `@matthewjasper` ❤️ for helping me with lowering to MIR! Would you be interested in reviewing this?
r? `@ghost` for now
