RS.CLIPPY.MANUAL_IGNORE_CASE_CMP

Manual case-insensitive ASCII comparison

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: manual_ignore_case_cmp. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks for manual case-insensitive ASCII comparison.

Why is this bad?

The eq_ignore_ascii_case method is faster because it does not allocate memory for the new strings, and it is more readable.

Example

fn compare(a: &str, b: &str) -> bool {
    a.to_ascii_lowercase() == b.to_ascii_lowercase() || a.to_ascii_lowercase() == "abc"
}

Use instead:

fn compare(a: &str, b: &str) -> bool {
    a.eq_ignore_ascii_case(b) || a.eq_ignore_ascii_case("abc")
}