Error code E0185

An associated function for a trait was defined to be static, but an implementation of the trait declared the same function to be a method (i.e., to take a self parameter).

Erroneous code example:

#![allow(unused)] fn main() { trait Foo { fn foo(); } struct Bar; impl Foo for Bar { // error, method `foo` has a `&self` declaration in the impl, but not in // the trait fn foo(&self) {} } }

When a type implements a trait's associated function, it has to use the same signature. So in this case, since Foo::foo does not take any argument and does not return anything, its implementation on Bar should be the same:

#![allow(unused)] fn main() { trait Foo { fn foo(); } struct Bar; impl Foo for Bar { fn foo() {} // ok! } }