Error code E0050

An attempted implementation of a trait method has the wrong number of function parameters.

Erroneous code example:

#![allow(unused)] fn main() { trait Foo { fn foo(&self, x: u8) -> bool; } struct Bar; // error: method `foo` has 1 parameter but the declaration in trait `Foo::foo` // has 2 impl Foo for Bar { fn foo(&self) -> bool { true } } }

For example, the Foo trait has a method foo with two function parameters (&self and u8), but the implementation of foo for the type Bar omits the u8 parameter. To fix this error, they must have the same parameters:

#![allow(unused)] fn main() { trait Foo { fn foo(&self, x: u8) -> bool; } struct Bar; impl Foo for Bar { fn foo(&self, x: u8) -> bool { // ok! true } } }