Normalize associated types in the type_is_newtype_immediate pass. Fixes #21010.

src/test/run-pass/associated-types-normalize-unifield-struct.rs

@@ -0,0 +1,32 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for issue #21010: Normalize associated types in
+// various special paths in the `type_is_immediate` function.
+
+#![allow(unstable)]
+
+pub trait OffsetState: Sized {}
+pub trait Offset { type State: OffsetState; }
+
+#[derive(Copy)] pub struct X;
+impl Offset for X { type State = Y; }
+
+#[derive(Copy)] pub struct Y;
+impl OffsetState for Y {}
+
+pub fn now() -> DateTime<X> { from_utc(Y) }
+
+pub struct DateTime<Off: Offset> { pub offset: Off::State }
+pub fn from_utc<Off: Offset>(offset: Off::State) -> DateTime<Off> { DateTime { offset: offset } }
+
+pub fn main() {
+    let _x = now();
+}