In Rust 1.15.1 and nightly (24a70eb59 2017-02-09) ```rust fn foo<A, B>() {} fn main() { foo::<u8>() } ``` Produces the error: ``` error[E0089]: too few type parameters provided: expected 2 parameters parameters, found 1 parameter parameter --> src/main.rs:4:5 | 4 | foo::<u8>() | ^^^^^^^^^ expected 2 type parameters ``` Specifically, my issue is with: > expected 2 **parameters parameters**, found 1 **parameter parameter**