An attempted implementation of a trait method has the wrong number of type or const parameters.
Erroneous code example:
trait Foo {
fn foo<T: Default>(x: T) -> Self;
}
struct Bar;
// error: method `foo` has 0 type parameters but its trait declaration has 1
// type parameter
impl Foo for Bar {
fn foo(x: bool) -> Self { Bar }
}For example, the Foo trait has a method foo with a type parameter T,
but the implementation of foo for the type Bar is missing this parameter.
To fix this error, they must have the same type parameters:
trait Foo {
fn foo<T: Default>(x: T) -> Self;
}
struct Bar;
impl Foo for Bar {
fn foo<T: Default>(x: T) -> Self { // ok!
Bar
}
}