`ToSource` implementation is incorrect for signed integers

[apasel422]

It appears that the syntax::ext::quote::rt::ToSource implementation for signed integer types omits the sign.

test.rs:

extern crate syntax;

#[test]
fn test() {
    use syntax::ext::quote::rt::ToSource;

    let n = -5i32;
    let s = n.to_source();
    assert_eq!(s, "-5i32".to_string());
}

Output after compiling with rustc 0.13.0-nightly (40b244973 2014-10-14 23:22:20 +0000):

task 'test' failed at 'assertion failed: `(left == right) && (right == left)` (left: `5i32`, right: `-5i32`)'

[robinst]

The problem seems to be here:

rust/src/libsyntax/print/pprust.rs

Line 2684 in 18062c1

ast_util::int_ty_to_string(st, Some(-(i as i64))).as_slice())

i is -5 as u64, so the above line passes Some(-((-5 as u64) as i64) to int_ty_to_string, which is Some(5). But then it doesn't add a - in front.

Where are the tests for this? Could try to write a fix.

[apasel422]

This was fixed by #18160.