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Auto merge of #11052 - Centri3:string_lit_chars_any, r=Jarcho

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New lint [`string_lit_chars_any`]

Closes #10389

This lint can probably be deprecated if/when rustc optimizes `.chars().any(...)`.

changelog: New lint [`string_lit_chars_any`]
This commit is contained in:
bors 2023-07-19 06:58:03 +00:00
commit ec571555a8
7 changed files with 256 additions and 1 deletions
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1
CHANGELOG.md
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@ -5256,6 +5256,7 @@ Released 2018-09-13
[`string_extend_chars`]: https://rust-lang.github.io/rust-clippy/master/index.html#string_extend_chars
[`string_from_utf8_as_bytes`]: https://rust-lang.github.io/rust-clippy/master/index.html#string_from_utf8_as_bytes
[`string_lit_as_bytes`]: https://rust-lang.github.io/rust-clippy/master/index.html#string_lit_as_bytes
[`string_lit_chars_any`]: https://rust-lang.github.io/rust-clippy/master/index.html#string_lit_chars_any
[`string_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#string_slice
[`string_to_string`]: https://rust-lang.github.io/rust-clippy/master/index.html#string_to_string
[`strlen_on_c_strings`]: https://rust-lang.github.io/rust-clippy/master/index.html#strlen_on_c_strings

1
clippy_lints/src/declared_lints.rs
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@ -405,6 +405,7 @@
crate::methods::SKIP_WHILE_NEXT_INFO,
crate::methods::STABLE_SORT_PRIMITIVE_INFO,
crate::methods::STRING_EXTEND_CHARS_INFO,
crate::methods::STRING_LIT_CHARS_ANY_INFO,
crate::methods::SUSPICIOUS_COMMAND_ARG_SPACE_INFO,
crate::methods::SUSPICIOUS_MAP_INFO,
crate::methods::SUSPICIOUS_SPLITN_INFO,

39
clippy_lints/src/methods/mod.rs
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@ -86,6 +86,7 @@
mod stable_sort_primitive;
mod str_splitn;
mod string_extend_chars;
mod string_lit_chars_any;
mod suspicious_command_arg_space;
mod suspicious_map;
mod suspicious_splitn;
@ -115,7 +116,7 @@
use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
use clippy_utils::msrvs::{self, Msrv};
use clippy_utils::ty::{contains_ty_adt_constructor_opaque, implements_trait, is_copy, is_type_diagnostic_item};
use clippy_utils::{contains_return, is_bool, is_trait_method, iter_input_pats, return_ty};
use clippy_utils::{contains_return, is_bool, is_trait_method, iter_input_pats, peel_blocks, return_ty};
use if_chain::if_chain;
use rustc_hir as hir;
use rustc_hir::{Expr, ExprKind, Node, Stmt, StmtKind, TraitItem, TraitItemKind};
@ -3379,6 +3380,34 @@
"calling `Stdin::read_line`, then trying to parse it without first trimming"
}
declare_clippy_lint! {
/// ### What it does
/// Checks for `<string_lit>.chars().any(|i| i == c)`.
///
/// ### Why is this bad?
/// It's significantly slower than using a pattern instead, like
/// `matches!(c, '\\' | '.' | '+')`.
///
/// Despite this being faster, this is not `perf` as this is pretty common, and is a rather nice
/// way to check if a `char` is any in a set. In any case, this `restriction` lint is available
/// for situations where that additional performance is absolutely necessary.
///
/// ### Example
/// ```rust
/// # let c = 'c';
/// "\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
/// ```
/// Use instead:
/// ```rust
/// # let c = 'c';
/// matches!(c, '\\' | '.' | '+' | '*' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
/// ```
#[clippy::version = "1.72.0"]
pub STRING_LIT_CHARS_ANY,
restriction,
"checks for `<string_lit>.chars().any(|i| i == c)`"
}
declare_clippy_lint! {
/// ### What it does
/// Checks for usage of `.map(|_| format!(..)).collect::<String>()`.
@ -3549,6 +3578,7 @@ pub fn new(
DRAIN_COLLECT,
MANUAL_TRY_FOLD,
FORMAT_COLLECT,
STRING_LIT_CHARS_ANY,
]);
/// Extracts a method call name, args, and `Span` of the method name.
@ -3923,6 +3953,13 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
}
}
},
("any", [arg]) if let ExprKind::Closure(arg) = arg.kind
&& let body = cx.tcx.hir().body(arg.body)
&& let [param] = body.params
&& let Some(("chars", recv, _, _, _)) = method_call(recv) =>
{
string_lit_chars_any::check(cx, expr, recv, param, peel_blocks(body.value), &self.msrv);
}
("nth", [n_arg]) => match method_call(recv) {
Some(("bytes", recv2, [], _, _)) => bytes_nth::check(cx, expr, recv2, n_arg),
Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false),

58
clippy_lints/src/methods/string_lit_chars_any.rs Normal file
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@ -0,0 +1,58 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::msrvs::{Msrv, MATCHES_MACRO};
use clippy_utils::source::snippet_opt;
use clippy_utils::{is_from_proc_macro, is_trait_method, path_to_local};
use itertools::Itertools;
use rustc_ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{BinOpKind, Expr, ExprKind, Param, PatKind};
use rustc_lint::LateContext;
use rustc_span::sym;
use super::STRING_LIT_CHARS_ANY;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'tcx>,
recv: &Expr<'_>,
param: &'tcx Param<'tcx>,
body: &Expr<'_>,
msrv: &Msrv,
) {
if msrv.meets(MATCHES_MACRO)
&& is_trait_method(cx, expr, sym::Iterator)
&& let PatKind::Binding(_, arg, _, _) = param.pat.kind
&& let ExprKind::Lit(lit_kind) = recv.kind
&& let LitKind::Str(val, _) = lit_kind.node
&& let ExprKind::Binary(kind, lhs, rhs) = body.kind
&& let BinOpKind::Eq = kind.node
&& let Some(lhs_path) = path_to_local(lhs)
&& let Some(rhs_path) = path_to_local(rhs)
&& let scrutinee = match (lhs_path == arg, rhs_path == arg) {
(true, false) => rhs,
(false, true) => lhs,
_ => return,
}
&& !is_from_proc_macro(cx, expr)
&& let Some(scrutinee_snip) = snippet_opt(cx, scrutinee.span)
{
// Normalize the char using `map` so `join` doesn't use `Display`, if we don't then
// something like `r"\"` will become `'\'`, which is of course invalid
let pat_snip = val.as_str().chars().map(|c| format!("{c:?}")).join(" | ");
span_lint_and_then(
cx,
STRING_LIT_CHARS_ANY,
expr.span,
"usage of `.chars().any(...)` to check if a char matches any from a string literal",
|diag| {
diag.span_suggestion_verbose(
expr.span,
"use `matches!(...)` instead",
format!("matches!({scrutinee_snip}, {pat_snip})"),
Applicability::MachineApplicable,
);
}
);
}
}

50
tests/ui/string_lit_chars_any.fixed Normal file
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@ -0,0 +1,50 @@
//@run-rustfix
//@aux-build:proc_macros.rs:proc-macro
#![allow(clippy::eq_op, clippy::needless_raw_string_hashes, clippy::no_effect, unused)]
#![warn(clippy::string_lit_chars_any)]
#[macro_use]
extern crate proc_macros;
struct NotStringLit;
impl NotStringLit {
fn chars(&self) -> impl Iterator<Item = char> {
"c".chars()
}
}
fn main() {
let c = 'c';
matches!(c, '\\' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
matches!(c, '\\' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
matches!(c, '\\' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
matches!(c, '\\' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
#[rustfmt::skip]
matches!(c, '\\' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
// Do not lint
NotStringLit.chars().any(|x| x == c);
"\\.+*?()|[]{}^$#&-~".chars().any(|x| {
let c = 'c';
x == c
});
"\\.+*?()|[]{}^$#&-~".chars().any(|x| {
1;
x == c
});
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == x);
"\\.+*?()|[]{}^$#&-~".chars().any(|_x| c == c);
matches!(
c,
'\\' | '.' | '+' | '*' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~'
);
external! {
let c = 'c';
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
}
with_span! {
span
let c = 'c';
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
}
}

50
tests/ui/string_lit_chars_any.rs Normal file
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@ -0,0 +1,50 @@
//@run-rustfix
//@aux-build:proc_macros.rs:proc-macro
#![allow(clippy::eq_op, clippy::needless_raw_string_hashes, clippy::no_effect, unused)]
#![warn(clippy::string_lit_chars_any)]
#[macro_use]
extern crate proc_macros;
struct NotStringLit;
impl NotStringLit {
fn chars(&self) -> impl Iterator<Item = char> {
"c".chars()
}
}
fn main() {
let c = 'c';
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
r#"\.+*?()|[]{}^$#&-~"#.chars().any(|x| x == c);
"\\.+*?()|[]{}^$#&-~".chars().any(|x| c == x);
r#"\.+*?()|[]{}^$#&-~"#.chars().any(|x| c == x);
#[rustfmt::skip]
"\\.+*?()|[]{}^$#&-~".chars().any(|x| { x == c });
// Do not lint
NotStringLit.chars().any(|x| x == c);
"\\.+*?()|[]{}^$#&-~".chars().any(|x| {
let c = 'c';
x == c
});
"\\.+*?()|[]{}^$#&-~".chars().any(|x| {
1;
x == c
});
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == x);
"\\.+*?()|[]{}^$#&-~".chars().any(|_x| c == c);
matches!(
c,
'\\' | '.' | '+' | '*' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~'
);
external! {
let c = 'c';
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
}
with_span! {
span
let c = 'c';
"\\.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
}
}

58
tests/ui/string_lit_chars_any.stderr Normal file
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@ -0,0 +1,58 @@
error: usage of `.chars().any(...)` to check if a char matches any from a string literal
--> $DIR/string_lit_chars_any.rs:19:5
|
LL | "//.+*?()|[]{}^$#&-~".chars().any(|x| x == c);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `-D clippy::string-lit-chars-any` implied by `-D warnings`
help: use `matches!(...)` instead
|
LL | matches!(c, '//' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: usage of `.chars().any(...)` to check if a char matches any from a string literal
--> $DIR/string_lit_chars_any.rs:20:5
|
LL | r#"/.+*?()|[]{}^$#&-~"#.chars().any(|x| x == c);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: use `matches!(...)` instead
|
LL | matches!(c, '//' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: usage of `.chars().any(...)` to check if a char matches any from a string literal
--> $DIR/string_lit_chars_any.rs:21:5
|
LL | "//.+*?()|[]{}^$#&-~".chars().any(|x| c == x);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: use `matches!(...)` instead
|
LL | matches!(c, '//' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: usage of `.chars().any(...)` to check if a char matches any from a string literal
--> $DIR/string_lit_chars_any.rs:22:5
|
LL | r#"/.+*?()|[]{}^$#&-~"#.chars().any(|x| c == x);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: use `matches!(...)` instead
|
LL | matches!(c, '//' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: usage of `.chars().any(...)` to check if a char matches any from a string literal
--> $DIR/string_lit_chars_any.rs:24:5
|
LL | "//.+*?()|[]{}^$#&-~".chars().any(|x| { x == c });
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: use `matches!(...)` instead
|
LL | matches!(c, '//' | '.' | '+' | '*' | '?' | '(' | ')' | '|' | '[' | ']' | '{' | '}' | '^' | '$' | '#' | '&' | '-' | '~');
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 5 previous errors