rustc hangs when printing block with no trailing newline

[lilyball]

If rustc attempts to print an error message for a block that has no trailing newline, because it ends on the very last line of a file with no trailing newline, then rustc will hang forever attempting to print the block.

To test, the following code should print a lifetime error:

fn main() {
    let x = Some(3);
    let y = x.as_ref().unwrap_or(&5);
}

If the file has a trailing newline, it prints just fine. But without the trailing newline, it hangs forever after printing:

foo.rs:3:34: 3:36 error: borrowed value does not live long enough
foo.rs:3     let y = x.as_ref().unwrap_or(&5);
                                          ^~
foo.rs:1:11: 1:1 note: reference must be valid for the block at 1:10...
foo.rs:1 fn main() {

[alexcrichton]

This appears to have been fixed, flagging as needstest.

[richo]

I had a stab at a testcase for this.