That code doesn't compile. :) If you're ever curious about something like this, feel free to use the online playground, like so: https://play.rust-lang.org/?gist=c3c93fb796d5fa79f829baa3dec...

Here's the compiler error that you'd get:

    error[E0308]: mismatched types
     --> src/main.rs:7:13
      |
    7 |       foo32(x);
      |             ^ expected f32, found f64
    
    error[E0308]: mismatched types
      --> src/main.rs:13:13
       |
    13 |       foo64(x);
       |             ^ expected f64, found f32