diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs index f04ac8dd9426f..7a42e8c1037ba 100644 --- a/compiler/rustc_lint/src/unused.rs +++ b/compiler/rustc_lint/src/unused.rs @@ -461,13 +461,16 @@ trait UnusedDelimLint { let lhs_needs_parens = { let mut innermost = inner; loop { - if let ExprKind::Binary(_, lhs, _rhs) = &innermost.kind { - innermost = lhs; - if !classify::expr_requires_semi_to_be_stmt(innermost) { - break true; - } - } else { - break false; + innermost = match &innermost.kind { + ExprKind::Binary(_, lhs, _rhs) => lhs, + ExprKind::Call(fn_, _params) => fn_, + ExprKind::Cast(expr, _ty) => expr, + ExprKind::Type(expr, _ty) => expr, + ExprKind::Index(base, _subscript) => base, + _ => break false, + }; + if !classify::expr_requires_semi_to_be_stmt(innermost) { + break true; } } }; diff --git a/src/test/ui/lint/unused/issue-88519-unused-paren.rs b/src/test/ui/lint/unused/issue-88519-unused-paren.rs new file mode 100644 index 0000000000000..be02fcd3f00c7 --- /dev/null +++ b/src/test/ui/lint/unused/issue-88519-unused-paren.rs @@ -0,0 +1,94 @@ +// check-pass +// Make sure unused parens lint doesn't emit a false positive. +// See https://github.com/rust-lang/rust/issues/88519 +#![deny(unused_parens)] +#![feature(type_ascription)] + +// binary ops are tested in issue-71290-unused-paren-binop.rs + +mod call { + fn noop() -> u8 { 0 } + fn outside() -> u8 { + ({ noop })() + } + fn inside() -> u8 { + ({ noop }()) + } + fn outside_match() -> u8 { + (match noop { x => x })() + } + fn inside_match() -> u8 { + (match noop { x => x }()) + } + fn outside_if() -> u8 { + (if false { noop } else { noop })() + } + fn inside_if() -> u8 { + (if false { noop } else { noop }()) + } +} + +mod casts { + fn outside() -> u8 { + ({ 0 }) as u8 + } + fn inside() -> u8 { + ({ 0 } as u8) + } + fn outside_match() -> u8 { + (match 0 { x => x }) as u8 + } + fn inside_match() -> u8 { + (match 0 { x => x } as u8) + } + fn outside_if() -> u8 { + (if false { 0 } else { 0 }) as u8 + } + fn inside_if() -> u8 { + (if false { 0 } else { 0 } as u8) + } +} + +mod typeascription { + fn outside() -> u8 { + ({ 0 }): u8 + } + fn inside() -> u8 { + ({ 0 }: u8) + } + fn outside_match() -> u8 { + (match 0 { x => x }): u8 + } + fn inside_match() -> u8 { + (match 0 { x => x }: u8) + } + fn outside_if() -> u8 { + (if false { 0 } else { 0 }): u8 + } + fn inside_if() -> u8 { + (if false { 0 } else { 0 }: u8) + } +} + +mod index { + fn outside(x: &[u8]) -> u8 { + ({ x })[0] + } + fn inside(x: &[u8]) -> u8 { + ({ x }[0]) + } + fn outside_match(x: &[u8]) -> u8 { + (match x { x => x })[0] + } + fn inside_match(x: &[u8]) -> u8 { + (match x { x => x }[0]) + } + fn outside_if(x: &[u8]) -> u8 { + (if false { x } else { x })[0] + } + fn inside_if(x: &[u8]) -> u8 { + (if false { x } else { x }[0]) + } +} + +fn main() {}