Error code E0415

More than one function parameter have the same name.

Erroneous code example:

#![allow(unused)]
fn main() {
fn foo(f: i32, f: i32) {} // error: identifier `f` is bound more than
                          //        once in this parameter list
}

Please verify you didn't misspell parameters' name. Example:

#![allow(unused)]
fn main() {
fn foo(f: i32, g: i32) {} // ok!
}