[rustc.git] / src / librustc_error_codes / error_codes / E0281.md

#### Note: this error code is no longer emitted by the compiler.

You tried to supply a type which doesn't implement some trait in a location
which expected that trait. This error typically occurs when working with
`Fn`-based types. Erroneous code example:

```compile-fail
fn foo<F: Fn(usize)>(x: F) { }

fn main() {
    // type mismatch: ... implements the trait `core::ops::Fn<(String,)>`,
    // but the trait `core::ops::Fn<(usize,)>` is required
    // [E0281]
    foo(|y: String| { });
}
```

The issue in this case is that `foo` is defined as accepting a `Fn` with one
argument of type `String`, but the closure we attempted to pass to it requires
one arguments of type `usize`.
Commit	Line	Data
d9bb1a4e FG	1	#### Note: this error code is no longer emitted by the compiler.
	2
	3	You tried to supply a type which doesn't implement some trait in a location
	4	which expected that trait. This error typically occurs when working with
	5	`Fn`-based types. Erroneous code example:
	6
	7	```compile-fail
	8	fn foo<F: Fn(usize)>(x: F) { }
	9
	10	fn main() {
	11	// type mismatch: ... implements the trait `core::ops::Fn<(String,)>`,
	12	// but the trait `core::ops::Fn<(usize,)>` is required
	13	// [E0281]
	14	foo(\|y: String\| { });
	15	}
	16	```
	17
	18	The issue in this case is that `foo` is defined as accepting a `Fn` with one
	19	argument of type `String`, but the closure we attempted to pass to it requires
	20	one arguments of type `usize`.