[pcwalton]

I fought to keep this feature around in Rust. I was inspired by OCaml (which the old Rust compiler was written in), where you could write:

    let x = foo() in
    let x = bar x in
    let x = baz x in
    print x

In a functional language where mutation is less convenient than in C++, this is really handy, and I wanted Rust to support the same idiom.