Generic types on functions outside of implementation blocks

It's possible to use generic type parameters for functions even when they're not part of an implementation block. That looks like this:

fn print_generic<T>(value: T) where T: Display {
    println!("{}", value);
}

This function has a generic type parameter, T, which can be any data type that has the Display trait. That means that, if this function is defined, we can do things like this:

print_generic(12.7);
print_generic("Hello");
print_generic(75);

Each of those lines calls a different print_generic function, specialized for the data type of the parameter. The compiler generates code for each version of print_generic that we use, each one accepting a different data type for its parameter.