Can't use enum variants when using enum as a generic type?-CodePudding

I'm having a E0599 (no associated item named Variant1 found for type parameter MyEnum in the current scope) error with the following code :

enum MyEnum {
    Variant1,
    Variant2,
    Variant3
}

struct MyStruct {}

trait MyTrait<T> {
    fn get_some_variant(self) -> T;
}

impl<MyEnum> MyTrait<MyEnum> for MyStruct {
    fn get_some_variant(self) -> MyEnum {
        MyEnum::Variant1
    }
}

Here is a Playground link.

Why can't I build a variant from my enum in this case ?

What are the workaround ? Are enums not meant to be used as generics ?

CodePudding user response：

impl<MyEnum> defines MyEnum as an arbitrary generic type, which is shadowing your actual MyEnum definition.

impl MyTrait<MyEnum> for MyStruct {
    fn get_some_variant(self) -> MyEnum {
        MyEnum::Variant1
    }
}

works as expected and creates an implementation for MyTrait<MyEnum>.