Error code E0642
Trait methods currently cannot take patterns as arguments.
Erroneous code example:
#![allow(unused)] fn main() { trait Foo { fn foo((x, y): (i32, i32)); // error: patterns aren't allowed // in trait methods } }
You can instead use a single name for the argument:
#![allow(unused)] fn main() { trait Foo { fn foo(x_and_y: (i32, i32)); // ok! } }