use std::fmt;

struct A;

impl fmt::Display for A {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "A")
    }
}

In this example, I'm able to call let a = A; a.to_string() since A implements fmt::Display. The generated documentation doesn't mention anything about to_string. It'd be great if the documentation displayed all available methods for a given structure.