Immutable binding becomes mutable in const block expression

[Kimundi]

Code (playpen):

static UINT: uint = {
    // BUG, allows assigning immutable variable x
    fn foo() -> uint {
        let x;
        x = 100;
        x = 200;
        x
    }
    100
};

// OK, produces a error about assigning immutable variable x
fn foo() -> uint {
    let x;
    x = 100;
    x = 200;
    x
}

fn main() {
    println!("{}", UINT)
}

Complete output:

<anon>:16:5: 16:12 error: re-assignment of immutable variable `x`
<anon>:16     x = 200;
              ^~~~~~~
<anon>:15:5: 15:12 note: prior assignment occurs here
<anon>:15     x = 100;
              ^~~~~~~
error: aborting due to previous error
playpen: application terminated with error code 101
Program ended.

[steveklabnik]

Very strange, but still a bug.

[steveklabnik]

This has gotten fixed somewhere down the line, as both error for me with usize.