New upstream version 1.66.0+dfsg1

[rustc.git] / src / tools / clippy / src / docs / new_ret_no_self.txt

### What it does
Checks for `new` not returning a type that contains `Self`.

### Why is this bad?
As a convention, `new` methods are used to make a new
instance of a type.

### Example
In an impl block:
```
impl Foo {
    fn new() -> NotAFoo {
    }
}
```

```
struct Bar(Foo);
impl Foo {
    // Bad. The type name must contain `Self`
    fn new() -> Bar {
    }
}
```

```
impl Foo {
    // Good. Return type contains `Self`
    fn new() -> Result<Foo, FooError> {
    }
}
```

Or in a trait definition:
```
pub trait Trait {
    // Bad. The type name must contain `Self`
    fn new();
}
```

```
pub trait Trait {
    // Good. Return type contains `Self`
    fn new() -> Self;
}
```