RS.CLIPPY.COMPARISON_TO_EMPTY

Checking `x == \"\"` or `x == []` (or similar) when `.is_empty()` could be used instead

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

What it does

Checks for comparing to an empty slice such as "" or [], and suggests using .is_empty() where applicable.

Why is this bad?

Some structures can answer .is_empty() much faster than checking for equality. So it is good to get into the habit of using .is_empty(), and having it is cheap. Besides, it makes the intent clearer than a manual comparison in some contexts.

Example

if s == "" {
    ..
}

if arr == [] {
    ..
}

Use instead:

if s.is_empty() {
    ..
}

if arr.is_empty() {
    ..
}