---

yaml
---
r: 170784
b: refs/heads/try
c: 540a777
h: refs/heads/master
v: v3

Author: nikomatsakis

[refs]

@@ -2,7 +2,7 @@
 refs/heads/master: 73a25f55ad748b4d3516417c711b99ce446591af
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: 5b3cd3900ceda838f5798c30ab96ceb41f962534
-refs/heads/try: c8868942e845254abfd3623a709847d65e015a2f
+refs/heads/try: 540a7777b8ba53950d340ee9537ede1b3fb0b24d
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596

branches/try/src/librustc/middle/traits/project.rs

@@ -643,11 +643,12 @@ fn confirm_candidate<'cx,'tcx>(
             match impl_ty {
                 Some(ty) => (ty, impl_vtable.nested.to_vec()),
                 None => {
-                    selcx.tcx().sess.span_bug(
-                        obligation.cause.span,
-                        format!("impl `{}` did not contain projection for `{}`",
-                                impl_vtable.repr(selcx.tcx()),
-                                obligation.repr(selcx.tcx())).as_slice());
+                    // This means that the impl is missing a
+                    // definition for the associated type. This error
+                    // ought to be reported by the type checker method
+                    // `check_impl_items_against_trait`, so here we
+                    // just return ty_err.
+                    (selcx.tcx().types.err, vec!())
                 }
             }
         }

branches/try/src/test/compile-fail/associated-types-issue-17359.rs

@@ -0,0 +1,23 @@
+// Copyright 2014 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.
+
+// Test that we do not ICE when an impl is missing an associated type (and that we report
+// a useful error, of course).
+
+#![feature(associated_types)]
+
+trait Trait {
+    type Type;
+}
+
+impl Trait for int {}  //~ ERROR missing: `Type`
+
+fn main() {}
+