Calling trait's static function from trait's implementation

testcase.rs

trait Foo {
  fn foo() -> int { 10 }
}

struct FooStruct;

impl Foo for FooStruct {
  fn bar(&self) {
    println!("Foo : {}", Foo::foo());
  }
}

fn main() {
  let foo = FooStruct;
  foo.foobar();
}

// testcase.rs:9:26: 9:34 error: cannot determine a type for this bounded type parameter: unconstrained type
// testcase.rs:9     println!("Foo : {}", Foo::foo());