RS.CLIPPY.NEW_WITHOUT_DEFAULT

`pub fn new() -> Self` method without `Default` implementation

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

What it does

Checks for public types with a pub fn new() -> Self method and no implementation of Default.

Why is this bad?

The user might expect to be able to use Default as the type can be constructed without arguments.

Example

pub struct Foo(Bar);

impl Foo {
    pub fn new() -> Self {
        Foo(Bar::new())
    }
}

To fix the lint, add a Default implementation that delegates to new:

pub struct Foo(Bar);

impl Default for Foo {
    fn default() -> Self {
        Foo::new()
    }
}

Past names

new_without_default_derive