ICE: ty_is_local invoked on unexpected type: [type error] implementing trait for undeclared type

[Ms2ger]

use std::fmt;

impl fmt::Display for DecoderError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Missing data: {}", self.0)
    }
}
fn main() {
}

/tmp/y:3:23: 3:35 error: use of undeclared type name `DecoderError` [E0412]
/tmp/y:3 impl fmt::Display for DecoderError {
                               ^~~~~~~~~~~~
/tmp/y:3:23: 3:35 help: run `rustc --explain E0412` to see a detailed explanation
error: internal compiler error: ty_is_local invoked on unexpected type: [type error]
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', ../src/libsyntax/errors/mod.rs:230