Error code E0186
An associated function for a trait was defined to be a method (i.e., to take a
self parameter), but an implementation of the trait declared the same function
to be static.
Erroneous code example:
#![allow(unused)] fn main() { trait Foo { fn foo(&self); } struct Bar; impl Foo for Bar { // error, method `foo` has a `&self` declaration in the trait, but not in // the impl fn foo() {} } }
When a type implements a trait's associated function, it has to use the same
signature. So in this case, since Foo::foo takes self as argument and
does not return anything, its implementation on Bar should be the same:
#![allow(unused)] fn main() { trait Foo { fn foo(&self); } struct Bar; impl Foo for Bar { fn foo(&self) {} // ok! } }