languages/rust
languages/rust
1
0
Fork 0
mirror of https://github.com/rust-lang/rust synced 2024-10-01 06:14:33 +00:00
Code Issues Packages Projects Releases Wiki Activity

Clean up E0371 explanation

Browse source
This commit is contained in:
Guillaume Gomez 2020-02-25 13:28:47 +01:00
parent f56042fb3c
commit d6f83c541d
1 changed files with 7 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
src/librustc_error_codes/error_codes/E0371.md
View file

@ -1,9 +1,6 @@
When `Trait2` is a subtrait of `Trait1` (for example, when `Trait2` has a
definition like `trait Trait2: Trait1 { ... }`), it is not allowed to implement
`Trait1` for `Trait2`. This is because `Trait2` already implements `Trait1` by
definition, so it is not useful to do this.
A trait was implemented on another which already automatically implemented it.
Example:
Erroneous code examples:
```compile_fail,E0371
trait Foo { fn foo(&self) { } }
@ -15,3 +12,8 @@ impl Foo for Baz { } // error, `Baz` implements `Bar` which implements `Foo`
impl Baz for Baz { } // error, `Baz` (trivially) implements `Baz`
impl Baz for Bar { } // Note: This is OK
```
When `Trait2` is a subtrait of `Trait1` (for example, when `Trait2` has a
definition like `trait Trait2: Trait1 { ... }`), it is not allowed to implement
`Trait1` for `Trait2`. This is because `Trait2` already implements `Trait1` by
definition, so it is not useful to do this.