75 lines
2.1 KiB
Rust
75 lines
2.1 KiB
Rust
use clippy_utils::diagnostics::span_lint;
|
|
use rustc_ast::ast::{Expr, ExprKind};
|
|
use rustc_lint::{EarlyContext, EarlyLintPass};
|
|
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
|
|
|
declare_clippy_lint! {
|
|
/// ### What it does
|
|
/// Checks for unnecessary double parentheses.
|
|
///
|
|
/// ### Why is this bad?
|
|
/// This makes code harder to read and might indicate a
|
|
/// mistake.
|
|
///
|
|
/// ### Example
|
|
/// ```rust
|
|
/// fn simple_double_parens() -> i32 {
|
|
/// ((0))
|
|
/// }
|
|
///
|
|
/// # fn foo(bar: usize) {}
|
|
/// foo((0));
|
|
/// ```
|
|
///
|
|
/// Use instead:
|
|
/// ```rust
|
|
/// fn simple_no_parens() -> i32 {
|
|
/// 0
|
|
/// }
|
|
///
|
|
/// # fn foo(bar: usize) {}
|
|
/// foo(0);
|
|
/// ```
|
|
#[clippy::version = "pre 1.29.0"]
|
|
pub DOUBLE_PARENS,
|
|
complexity,
|
|
"Warn on unnecessary double parentheses"
|
|
}
|
|
|
|
declare_lint_pass!(DoubleParens => [DOUBLE_PARENS]);
|
|
|
|
impl EarlyLintPass for DoubleParens {
|
|
fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
|
|
if expr.span.from_expansion() {
|
|
return;
|
|
}
|
|
|
|
let msg: &str = "consider removing unnecessary double parentheses";
|
|
|
|
match expr.kind {
|
|
ExprKind::Paren(ref in_paren) => match in_paren.kind {
|
|
ExprKind::Paren(_) | ExprKind::Tup(_) => {
|
|
span_lint(cx, DOUBLE_PARENS, expr.span, msg);
|
|
},
|
|
_ => {},
|
|
},
|
|
ExprKind::Call(_, ref params) => {
|
|
if params.len() == 1 {
|
|
let param = ¶ms[0];
|
|
if let ExprKind::Paren(_) = param.kind {
|
|
span_lint(cx, DOUBLE_PARENS, param.span, msg);
|
|
}
|
|
}
|
|
},
|
|
ExprKind::MethodCall(ref call) => {
|
|
if let [ref arg] = call.args[..] {
|
|
if let ExprKind::Paren(_) = arg.kind {
|
|
span_lint(cx, DOUBLE_PARENS, arg.span, msg);
|
|
}
|
|
}
|
|
},
|
|
_ => {},
|
|
}
|
|
}
|
|
}
|