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fix false positives for unused_parens around unary and binary operations

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This commit is contained in:
Lukas Markeffsky 2023-04-12 22:53:38 +02:00
parent e14b81f10d
commit 8df1f41b9c
4 changed files with 64 additions and 36 deletions
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48
compiler/rustc_lint/src/unused.rs
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@ -569,36 +569,48 @@ trait UnusedDelimLint {
}
}
// Prevent false-positives in cases like `fn x() -> u8 { ({ 0 } + 1) }`
let lhs_needs_parens = {
// Check if LHS needs parens to prevent false-positives in cases like `fn x() -> u8 { ({ 0 } + 1) }`.
{
let mut innermost = inner;
loop {
innermost = match &innermost.kind {
ExprKind::Binary(_, lhs, _rhs) => lhs,
ExprKind::Binary(_op, 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,
_ => break,
};
if !classify::expr_requires_semi_to_be_stmt(innermost) {
break true;
return true;
}
}
};
}
lhs_needs_parens
|| (followed_by_block
&& match &inner.kind {
ExprKind::Ret(_)
| ExprKind::Break(..)
| ExprKind::Yield(..)
| ExprKind::Yeet(..) => true,
ExprKind::Range(_lhs, Some(rhs), _limits) => {
matches!(rhs.kind, ExprKind::Block(..))
}
_ => parser::contains_exterior_struct_lit(&inner),
})
// Check if RHS needs parens to prevent false-positives in cases like `if (() == return) {}`.
if !followed_by_block {
return false;
}
let mut innermost = inner;
loop {
innermost = match &innermost.kind {
ExprKind::Unary(_op, expr) => expr,
ExprKind::Binary(_op, _lhs, rhs) => rhs,
ExprKind::AssignOp(_op, _lhs, rhs) => rhs,
ExprKind::Assign(_lhs, rhs, _span) => rhs,
ExprKind::Ret(_)
| ExprKind::Break(..)
| ExprKind::Yield(..)
| ExprKind::Yeet(..) => return true,
ExprKind::Range(_lhs, Some(rhs), _limits) => {
return matches!(rhs.kind, ExprKind::Block(..));
}
_ => return parser::contains_exterior_struct_lit(&inner),
}
}
}
fn emit_unused_delims_expr(