diff --git a/clippy_lints/src/double_parens.rs b/clippy_lints/src/double_parens.rs index d014efcde48d..ab6e47712120 100644 --- a/clippy_lints/src/double_parens.rs +++ b/clippy_lints/src/double_parens.rs @@ -1,5 +1,7 @@ -use clippy_utils::diagnostics::span_lint; +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::source::{HasSession, snippet_with_applicability}; use rustc_ast::ast::{Expr, ExprKind, MethodCall}; +use rustc_errors::Applicability; use rustc_lint::{EarlyContext, EarlyLintPass}; use rustc_session::declare_lint_pass; @@ -24,7 +26,7 @@ declare_clippy_lint! { /// Use instead: /// ```no_run /// fn simple_no_parens() -> i32 { - /// 0 + /// (0) /// } /// /// # fn foo(bar: usize) {} @@ -40,23 +42,51 @@ declare_lint_pass!(DoubleParens => [DOUBLE_PARENS]); impl EarlyLintPass for DoubleParens { fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) { - let span = match &expr.kind { - ExprKind::Paren(in_paren) if matches!(in_paren.kind, ExprKind::Paren(_) | ExprKind::Tup(_)) => expr.span, - ExprKind::Call(_, args) | ExprKind::MethodCall(box MethodCall { args, .. }) - if let [args] = &**args - && let ExprKind::Paren(_) = args.kind => - { - args.span + if expr.span.from_expansion() { + return; + } + + match &expr.kind { + // ((..)) + // ^^^^^^ expr + // ^^^^ inner + ExprKind::Paren(inner) if matches!(inner.kind, ExprKind::Paren(_) | ExprKind::Tup(_)) => { + // suggest removing the outer parens + let mut applicability = Applicability::MachineApplicable; + let sugg = snippet_with_applicability(cx.sess(), inner.span, "_", &mut applicability); + span_lint_and_sugg( + cx, + DOUBLE_PARENS, + expr.span, + "unnecessary parentheses", + "remove them", + sugg.to_string(), + applicability, + ); }, - _ => return, - }; - if !expr.span.from_expansion() { - span_lint( - cx, - DOUBLE_PARENS, - span, - "consider removing unnecessary double parentheses", - ); + + // func((n)) + // ^^^^^^^^^ expr + // ^^^ arg + // ^ inner + ExprKind::Call(_, args) | ExprKind::MethodCall(box MethodCall { args, .. }) + if let [arg] = &**args + && let ExprKind::Paren(inner) = &arg.kind => + { + // suggest removing the inner parens + let mut applicability = Applicability::MachineApplicable; + let sugg = snippet_with_applicability(cx.sess(), inner.span, "_", &mut applicability); + span_lint_and_sugg( + cx, + DOUBLE_PARENS, + arg.span, + "unnecessary parentheses", + "remove them", + sugg.to_string(), + applicability, + ); + }, + _ => {}, } } } diff --git a/tests/ui/double_parens.fixed b/tests/ui/double_parens.fixed new file mode 100644 index 000000000000..7fa116942fe8 --- /dev/null +++ b/tests/ui/double_parens.fixed @@ -0,0 +1,63 @@ +#![warn(clippy::double_parens)] +#![expect(clippy::eq_op)] +#![feature(custom_inner_attributes)] +#![rustfmt::skip] + +fn dummy_fn(_: T) {} + +struct DummyStruct; + +impl DummyStruct { + fn dummy_method(self, _: T) {} +} + +fn simple_double_parens() -> i32 { + (0) + //~^ double_parens +} + +fn fn_double_parens() { + dummy_fn(0); + //~^ double_parens +} + +fn method_double_parens(x: DummyStruct) { + x.dummy_method(0); + //~^ double_parens +} + +fn tuple_double_parens() -> (i32, i32) { + (1, 2) + //~^ double_parens +} + +#[allow(clippy::unused_unit)] +fn unit_double_parens() { + () + //~^ double_parens +} + +fn fn_tuple_ok() { + dummy_fn((1, 2)); +} + +fn method_tuple_ok(x: DummyStruct) { + x.dummy_method((1, 2)); +} + +fn fn_unit_ok() { + dummy_fn(()); +} + +fn method_unit_ok(x: DummyStruct) { + x.dummy_method(()); +} + +// Issue #3206 +fn inside_macro() { + assert_eq!((1, 2), (1, 2), "Error"); + assert_eq!((1, 2), (1, 2), "Error"); + //~^ double_parens +} + +fn main() {} diff --git a/tests/ui/double_parens.rs b/tests/ui/double_parens.rs index 1e0303361595..8730b4b12468 100644 --- a/tests/ui/double_parens.rs +++ b/tests/ui/double_parens.rs @@ -31,6 +31,7 @@ fn tuple_double_parens() -> (i32, i32) { //~^ double_parens } +#[allow(clippy::unused_unit)] fn unit_double_parens() { (()) //~^ double_parens diff --git a/tests/ui/double_parens.stderr b/tests/ui/double_parens.stderr index da48219c97e1..2b37877ccdd8 100644 --- a/tests/ui/double_parens.stderr +++ b/tests/ui/double_parens.stderr @@ -1,41 +1,41 @@ -error: consider removing unnecessary double parentheses +error: unnecessary parentheses --> tests/ui/double_parens.rs:15:5 | LL | ((0)) - | ^^^^^ + | ^^^^^ help: remove them: `(0)` | = note: `-D clippy::double-parens` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::double_parens)]` -error: consider removing unnecessary double parentheses +error: unnecessary parentheses --> tests/ui/double_parens.rs:20:14 | LL | dummy_fn((0)); - | ^^^ + | ^^^ help: remove them: `0` -error: consider removing unnecessary double parentheses +error: unnecessary parentheses --> tests/ui/double_parens.rs:25:20 | LL | x.dummy_method((0)); - | ^^^ + | ^^^ help: remove them: `0` -error: consider removing unnecessary double parentheses +error: unnecessary parentheses --> tests/ui/double_parens.rs:30:5 | LL | ((1, 2)) - | ^^^^^^^^ + | ^^^^^^^^ help: remove them: `(1, 2)` -error: consider removing unnecessary double parentheses - --> tests/ui/double_parens.rs:35:5 +error: unnecessary parentheses + --> tests/ui/double_parens.rs:36:5 | LL | (()) - | ^^^^ + | ^^^^ help: remove them: `()` -error: consider removing unnecessary double parentheses - --> tests/ui/double_parens.rs:58:16 +error: unnecessary parentheses + --> tests/ui/double_parens.rs:59:16 | LL | assert_eq!(((1, 2)), (1, 2), "Error"); - | ^^^^^^^^ + | ^^^^^^^^ help: remove them: `(1, 2)` error: aborting due to 6 previous errors