Trait UnusedDelimLint

trait UnusedDelimLint {
    const DELIM_STR: &'static str;
    const LINT_EXPR_IN_PATTERN_MATCHING_CTX: bool;

    // Required methods
    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>,
        is_kw: bool,
    );

    // Provided methods
    fn is_expr_delims_necessary(
        inner: &Expr,
        ctx: UnusedDelimsCtx,
        followed_by_block: bool,
    ) -> bool { ... }
    fn emit_unused_delims_expr(
        &self,
        cx: &EarlyContext<'_>,
        value: &Expr,
        ctx: UnusedDelimsCtx,
        left_pos: Option<BytePos>,
        right_pos: Option<BytePos>,
        is_kw: bool,
    ) { ... }
    fn emit_unused_delims(
        &self,
        cx: &EarlyContext<'_>,
        value_span: Span,
        spans: Option<(Span, Span)>,
        msg: &str,
        keep_space: (bool, bool),
        is_kw: 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) { ... }
}

Used by both UnusedParens and UnusedBraces to prevent code duplication.

Required Associated Constants

const DELIM_STR: &'static str

const LINT_EXPR_IN_PATTERN_MATCHING_CTX: bool

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

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>, is_kw: bool, )

Provided Methods

fn is_expr_delims_necessary( inner: &Expr, ctx: UnusedDelimsCtx, followed_by_block: bool, ) -> bool

fn emit_unused_delims_expr( &self, cx: &EarlyContext<'_>, value: &Expr, ctx: UnusedDelimsCtx, left_pos: Option<BytePos>, right_pos: Option<BytePos>, is_kw: bool, )

fn emit_unused_delims( &self, cx: &EarlyContext<'_>, value_span: Span, spans: Option<(Span, Span)>, msg: &str, keep_space: (bool, bool), is_kw: 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)

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl UnusedDelimLint for UnusedBraces

const DELIM_STR: &'static str = "braces"

const LINT_EXPR_IN_PATTERN_MATCHING_CTX: bool = false

impl UnusedDelimLint for UnusedParens

const DELIM_STR: &'static str = "parentheses"

const LINT_EXPR_IN_PATTERN_MATCHING_CTX: bool = true