Removing the semicolon of the last statement of an expressionless block
may change the block type even if the statement's type is `()`. If the
block type is `!` because of a systematic early return, typing it as
`()` may make it incompatible with the expected type for the block (to
which `!` is cast).
fix#13959
The current implementation of the `write_literal` and `print_literal`
lint performs escaping for the second argument of `write!` ,`writeln!`,
`print!` and `println!` of the suggestion by first replacing `"` with
`\"`, and then replacing `\` with `\\`. Performing these replacements in
this order may lead to unnecessary backslashes being added if the
original code contains `"` (e.g. `"` -> `\\"`), potentially resulting in
a suggestion that causes the code to fail to compile.
In the issue mentioned above, it’s suggested to use raw strings as raw
strings, but implementing this would require an ad-hoc change to the
current implementation, so it has been deferred. (I'll implement this in
another PR)
changelog: [`write_literal`]: fix incorrect escaping of suggestions
changelog: [`print_literal`]: fix incorrect escaping of suggestions
Add a new lint `doc_overindented_list_items` to detect and fix list items
in docs that are overindented.
For example,
```rs
/// - first line
/// second line
fn foo() {}
```
this would be fixed to:
```rs
/// - first line
/// second line
fn foo() {}
```
This lint improves readabiliy and consistency in doc.
fix#14034
The currect implementation of `obfuscated_if_else` sometimes makes
incorrect suggestions when the original code have side effects (see the
example in the above issue). I think this can be fixed by changing the
applicability depending on whether it can have side effects or not.
changelog: [`obfuscated_if_else`]: change applicability when the
original code can have side effects
I opened https://github.com/rust-lang/rust-clippy/pull/13896 before.
However, I found that there're more cases where Clippy suggests to use
modules that belong to the `std` crate even in a `no_std` environment.
Therefore, this PR include the changes I've made in #13896 and new
changes to fix cases I found this time to prevent wrong suggestions in
`no_std` environments as well.
changelog: [`redundant_closure`]: correct suggestion in `no_std`
changelog: [`repeat_vec_with_capacity`]: correct suggestion in `no_std`
changelog: [`single_range_in_vec_init`]: don't emit suggestion to use
`Vec` in `no_std`
changelog: [`drain_collect`]: correct suggestion in `no_std`
changelog: [`map_with_unused_argument_over_ranges`]: correct suggestion
in `no_std`
also close#13895
Uplift `clippy::double_neg` lint as `double_negations`
Warns about cases like this:
```rust
fn main() {
let x = 1;
let _b = --x; //~ WARN use of a double negation
}
```
The intent is to keep people from thinking that `--x` is a prefix decrement operator. `++x`, `x++` and `x--` are invalid expressions and already have a helpful diagnostic.
I didn't add a machine-applicable suggestion to the lint because it's not entirely clear what the programmer was trying to achieve with the `--x` operation. The code that triggers the lint should always be reviewed manually.
Closes#82987
Receivers which are references to `Option` and `Result`, or who
implement `Deref` to one of those types, will be linted as well.
changelog: [`unnecessary_map_or`]: work with ref and `Deref` to `Option`
and `Result` as well
Fixes#14023
**Note:** this patch must be merged after #13998 – only the second
commit must be reviewed, the first one repeats the patch in #13998 for
mergeability reasons.
Get rid of `mir::Const::from_ty_const`
This function is strange, because it turns valtrees into `mir::Const::Value`, but the rest of the const variants stay as type system consts.
All of the callsites except for one in `instsimplify` (array length simplification of `ptr_metadata` call) just go through the valtree arm of the function, so it's easier to just create a `mir::Const` directly for those.
For the instsimplify case, if we have a type system const we should *keep* having a type system const, rather than turning it into a `mir::Const::Value`; it doesn't really matter in practice, though, bc `usize` has no padding, but it feels more principled.
part of https://github.com/rust-lang/rust-clippy/issues/9100
The `obfuscated_if_else` lint currently only triggers for the pattern
`.then_some(..).unwrap_or(..)`, but there're other cases where this lint
should be triggered, one of which is `.then(..).unwrap_or(..)`.
changelog: [`obfuscated_if_else`]: trigger lint for the
`.then(..).unwrap_or(..)` pattern as well
changelog: none
`x & 15 == 0` is not equivalent to `x.trailing_zeros() > 4`, as `x =
0b10000` is true for the former and false for the latter.
In fact, clippy itself suggests the following:
```rust
pub fn src(x: i32) -> bool {
x & 15 == 0 // ~error: bit mask could be simplified with a call to `trailing_zeros`
^^^^^^^^^^^ help: try: `x.trailing_zeros() >= 4`
}
```
I ran across this message while writing code and thought it was quite
odd. I've simplified it and hopefully made it clearer for non-native
English speakers.
changelog: clarify message for non-obvious precedence
Without this check, the lint would suggest that
```rust
match test {
true if option == 5 => 10,
_ => 1,
};
```
is replaced by `if test { 10 } else { 1 }`.
changelog: [`match_bool`]: omit suggestion when guards are present in
`match` expression
Before edition 2024, some temporaries used in scrutinees of a `match`
used as the last expression of a block may outlive some referenced local
variables. Prevent those cases from happening by checking that alive
temporaries with significant drop do have a static lifetime.
The check is performed only for edition 2021 and earlier, and for the
last statement if it would become the last expression of the block.
changelog: [`unnecessary_semicolon`]: prevent borrow errors in editions
lower than 2024
r? @y21
Using `Vec::extend(std::iter::repeat_n(item, N))` allows to use the more
natural number of elements to add `N`, as is probably done in the
original loop, instead of computing the difference between the existing
number of elements and the wanted one.
Before MSRV 1.82, the older suggestion to use `Vec::resize()` is still
issued.
Inspired by #6156 (which predates `repeat_n()`).
changelog: [`same_item_push`]: recommend using `Vec::extend()` to extend
a vector
Before edition 2024, some temporaries used in scrutinees in a `match`
used as the last expression of a block may outlive some referenced
local variables. Prevent those cases from happening by checking that
alive temporaries with significant drop do have a static lifetime.
The check is performed only for edition 2021 and earlier, and for the
last statement if it would become the last expression of the block.
- The lint no longer triggers if one of the operands in the boolean
expression comes from a macro expansion.
- Parenthesis are now removed inside the generated block if they are no
longer necessary.
- Error markers have been added.
changelog: [`short_circuit_statement`]: better handling of macros and
better looking suggestions
changelog: none
`x & 15 == 0` is not equivalent to `x.trailing_zeros() > 4`, as `x = 0b10000` is true for
the former and false for the latter.
In fact, clippy itself suggests the following:
```rust
pub fn src(x: i32) -> bool {
x & 15 == 0 // ~error: bit mask could be simplified with a call to `trailing_zeros`
^^^^^^^^^^^ help: try: `x.trailing_zeros() >= 4`
}
```
