src/test/ui/issues/issue-43420-no-over-suggest.rs

// check that we substitute type parameters before we suggest anything - otherwise
// we would suggest function such as `as_slice` for the `&[u16]`.

fn foo(b: &[u16]) {}

fn main() {
    let a: Vec<u8> = Vec::new();
    foo(&a); //~ ERROR mismatched types
}