dylint

suboptimal_pattern

What it does

Checks for patterns that could perform additional destructuring.

Why is this bad?

The use of destructuring patterns in closure parameters (for example) often leads to more concise closure bodies. Beyond that, the benefits of this lint are similar to those of pattern-type-mismatch.

Known problems

• Currently only checks closure parameters (not, e.g., match patterns).
• Currently only suggests destructuring references and tuples (not, e.g., arrays or structs).
• For the lint to suggest destructuring a reference, the idents involved must not use ref annotations.

Example

let xs = [0, 1, 2];
let ys = xs.iter().map(|x| *x == 0).collect::<Vec<_>>();

Use instead:

let xs = [0, 1, 2];
let ys = xs.iter().map(|&x| x == 0).collect::<Vec<_>>();

Configuration

• explicit_deref_check: bool (default true): By default, suboptimal_pattern will not suggest to destructure a reference unless it would eliminate at least one explicit dereference. Setting explicit_deref_check to false disables this check.

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