Trait rustc_lint::unused::UnusedDelimLint

source · [−]
trait UnusedDelimLint {
    const DELIM_STR: &'static str;
    const LINT_EXPR_IN_PATTERN_MATCHING_CTX: bool;

    fn lint(&self) -> &'static Lint;
    fn check_unused_delims_expr(
        &self,
        cx: &EarlyContext<'_>,
        value: &Expr,
        ctx: UnusedDelimsCtx,
        followed_by_block: bool,
        left_pos: Option<BytePos>,
        right_pos: Option<BytePos>
    );

    fn is_expr_delims_necessary(
        inner: &Expr,
        followed_by_block: bool,
        followed_by_else: bool
    ) -> bool { ... }
    fn emit_unused_delims_expr(
        &self,
        cx: &EarlyContext<'_>,
        value: &Expr,
        ctx: UnusedDelimsCtx,
        left_pos: Option<BytePos>,
        right_pos: Option<BytePos>
    ) { ... }
    fn emit_unused_delims(
        &self,
        cx: &EarlyContext<'_>,
        value_span: Span,
        spans: Option<(Span, Span)>,
        msg: &str,
        keep_space: (bool, bool)
    ) { ... }
    fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) { ... }
    fn check_stmt(&mut self, cx: &EarlyContext<'_>, s: &Stmt) { ... }
    fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) { ... }
}
Expand description

Used by both UnusedParens and UnusedBraces to prevent code duplication.

Required Associated Constants

Due to ref pattern, there can be a difference between using { expr } and expr in pattern-matching contexts. This means that we should only lint unused_parens and not unused_braces in this case.

let mut a = 7;
let ref b = { a }; // We actually borrow a copy of `a` here.
a += 1; // By mutating `a` we invalidate any borrows of `a`.
assert_eq!(b + 1, a); // `b` does not borrow `a`, so we can still use it here.

Required Methods

Provided Methods

Implementors