Something other than a type or an associated type was given.
Erroneous code example:
enum Rick { Morty }
let _: <u8 as Rick>::Morty; // error!
trait Age {
type Empire;
fn Mythology() {}
}
impl Age for u8 {
type Empire = u16;
}
let _: <u8 as Age>::Mythology; // error!
RunIn both cases, we’re declaring a variable (called _
) and we’re giving it a
type. However, <u8 as Rick>::Morty
and <u8 as Age>::Mythology
aren’t types,
therefore the compiler throws an error.
<u8 as Rick>::Morty
is an enum variant, you cannot use a variant as a type,
you have to use the enum directly:
enum Rick { Morty }
let _: Rick; // ok!
Run<u8 as Age>::Mythology
is a trait method, which is definitely not a type.
However, the Age
trait provides an associated type Empire
which can be
used as a type:
trait Age {
type Empire;
fn Mythology() {}
}
impl Age for u8 {
type Empire = u16;
}
let _: <u8 as Age>::Empire; // ok!
Run