[rustc.git] / src / librustc_error_codes / error_codes / E0437.md

An associated type whose name does not match any of the associated types
in the trait was used when implementing the trait.

Erroneous code example:

```compile_fail,E0437
trait Foo {}

impl Foo for i32 {
    type Bar = bool;
}
```

Trait implementations can only implement associated types that are members of
the trait in question.

The solution to this problem is to remove the extraneous associated type:

```
trait Foo {}

impl Foo for i32 {}
```
Commit	Line	Data
ba9703b0 XL	1	An associated type whose name does not match any of the associated types
ba9703b0 XL	2	in the trait was used when implementing the trait.
60c5eb7d XL	3
	4	Erroneous code example:
	5
	6	```compile_fail,E0437
	7	trait Foo {}
	8
	9	impl Foo for i32 {
	10	type Bar = bool;
	11	}
	12	```
	13
ba9703b0 XL	14	Trait implementations can only implement associated types that are members of
	15	the trait in question.
	16
60c5eb7d XL	17	The solution to this problem is to remove the extraneous associated type:
	18
	19	```
	20	trait Foo {}
	21
	22	impl Foo for i32 {}
	23	```