use std::marker; struct Foo<T,U>(T, marker::PhantomData<U>); fn main() { match Foo(1.1, marker::PhantomData) { 1 => {} //~^ ERROR mismatched types //~| expected struct `Foo<{float}, _>` //~| found type `{integer}` //~| expected `Foo<{float}, _>`, found integer } }