Issue 1:
I was trying to build https://github.com/maurizi/rgtk/tree/update-to-latest-master

The backtrace is below:

$ RUST_BACKTRACE=1 cargo build --verbose
Fresh pkg-config v0.1.3
Fresh gcc v0.1.3
Compiling rgtk v0.0.1 (file:///home/mike/projects/rust-stuff/rgtk)
Running `rustc src/rgtk.rs --crate-name rgtk --crate-type rlib -g -C metadata=cec106287d6301f5 -C extra-filename=-cec106287d6301f5 --out-dir /home/mike/projects/rust-stuff/rgtk/target --emit=dep-info,link -L /home/mike/projects/rust-stuff/rgtk/target -L /home/mike/projects/rust-stuff/rgtk/target/deps -L native=/usr/lib/x86_64-linux-gnu -L native=/home/mike/projects/rust-stuff/rgtk/target/build/rgtk-cec106287d6301f5/out -L /home/mike/projects/rust-stuff/rgtk/target/build/rgtk-cec106287d6301f5/out -l gtk-3 -l gdk-3 -l pangocairo-1.0 -l pango-1.0 -l atk-1.0 -l cairo-gobject -l cairo -l gdk_pixbuf-2.0 -l gio-2.0 -l gobject-2.0 -l glib-2.0 -l rgtk_glue:static -l rgtk_glue:static`
<std macros>:5:11: 5:71 warning: `deriving` is deprecated; use `derive`
<std macros>:5 #[deriving(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<std macros>:5:11: 5:71 warning: `deriving` is deprecated; use `derive`
<std macros>:5 #[deriving(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/cairo/paths.rs:83:1: 107:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 238989 }:cairo::paths::PathSegments<'a>.Iterator, substs=Substs[types=[[];[];[]], regions=[['_#0r];[];[]]], nested=[[];[];[]])` did not contain projection for `Obligation(predicate=<cairo::paths::PathSegments<'a> as TraitRef(cairo::paths::PathSegments<'a>, core::iter::Iterator)>::Item,depth=0)`
src/cairo/paths.rs:83 impl<'a> Iterator for PathSegments<'a> {
src/cairo/paths.rs:84 fn next(&mut self) -> Option<PathSegment> {
src/cairo/paths.rs:85 let i = self.i;
src/cairo/paths.rs:86
src/cairo/paths.rs:87 if i >= self.num_data{
src/cairo/paths.rs:88 return None;
...
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:123

stack backtrace:
1: 0x7ffa22e142d0 - sys::backtrace::write::h8532e701ef86014f4it
2: 0x7ffa22e39b00 - failure::on_fail::h7532e1f79d134d5dzvz
3: 0x7ffa22d9f1c0 - rt::unwind::begin_unwind_inner::h97b151606151d62deaz
4: 0x7ffa1dc51c60 - rt::unwind::begin_unwind::h15809447133099964284
5: 0x7ffa1dc51bf0 - diagnostic::SpanHandler::span_bug::he8142ababcc30c39DFF
6: 0x7ffa21150e70 - middle::traits::project::project_type::h947eece142ef049d52P
7: 0x7ffa2114dfd0 - middle::traits::project::opt_normalize_projection_type::hb3defb9cc9365d1e8UP
8: 0x7ffa2113bba0 - middle::traits::project::normalize_projection_type::hdc293893275ee559JTP
9: 0x7ffa2114f470 - middle::traits::project::AssociatedTypeNormalizer<'a, 'b, 'tcx>.TypeFolder<'tcx>::fold_ty::h801cbd2cdff2eff1kSP
10: 0x7ffa2240c2e0 - middle::ty_fold::Rc<T>.TypeFoldable<'tcx>::fold_with::h6325524173844043840
11: 0x7ffa2240ce90 - middle::ty_fold::VecPerParamSpace<T>.TypeFoldable<'tcx>::fold_with::h13884369302522804796
12: 0x7ffa22428280 - check::FnCtxt<'a, 'tcx>::instantiate_bounds::hed550a9659b70335Oll
13: 0x7ffa22440fc0 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::check_impl::closure.29997
14: 0x7ffa2243d430 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::with_fcx::hb1283961ed8977b7Gfi
15: 0x7ffa22443d70 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::h001ababd87597e37soi
16: 0x7ffa22445bd0 - visit::walk_mod::h4610212675369237127
17: 0x7ffa22443d70 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::h001ababd87597e37soi
18: 0x7ffa22445bd0 - visit::walk_mod::h4610212675369237127
19: 0x7ffa22443d70 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::h001ababd87597e37soi
20: 0x7ffa22630fe0 - check_crate::unboxed_closure.40162
21: 0x7ffa2262bc30 - check_crate::h19fb6dea5733566ajsx
22: 0x7ffa23365640 - driver::phase_3_run_analysis_passes::h46b1604d9f9f5633Tva
23: 0x7ffa23353ae0 - driver::compile_input::h68b8602933aad8d7wba
24: 0x7ffa2341eeb0 - thunk::F.Invoke<A, R>::invoke::h18029802347644288836
25: 0x7ffa2341dc60 - rt::unwind::try::try_fn::h6518866316425934196
26: 0x7ffa22ea0400 - rust_try_inner
27: 0x7ffa22ea03f0 - rust_try
28: 0x7ffa2341dfb0 - thunk::F.Invoke<A, R>::invoke::h15513809553472565307
29: 0x7ffa22e25e40 - sys::thread::thread_start::h5ea7ba97235331d5a9v
30: 0x7ffa1d474fe0 - start_thread
31: 0x7ffa22a46749 - __clone
32: 0x0 - <unknown>

Could not compile `rgtk`.

Caused by:
Process didn't exit successfully: `rustc src/rgtk.rs --crate-name rgtk --crate-type rlib -g -C metadata=cec106287d6301f5 -C extra-filename=-cec106287d6301f5 --out-dir /home/mike/projects/rust-stuff/rgtk/target --emit=dep-info,link -L /home/mike/projects/rust-stuff/rgtk/target -L /home/mike/projects/rust-stuff/rgtk/target/deps -L native=/usr/lib/x86_64-linux-gnu -L native=/home/mike/projects/rust-stuff/rgtk/target/build/rgtk-cec106287d6301f5/out -L /home/mike/projects/rust-stuff/rgtk/target/build/rgtk-cec106287d6301f5/out -l gtk-3 -l gdk-3 -l pangocairo-1.0 -l pango-1.0 -l atk-1.0 -l cairo-gobject -l cairo -l gdk_pixbuf-2.0 -l gio-2.0 -l gobject-2.0 -l glib-2.0 -l rgtk_glue:static -l rgtk_glue:static` (status=101)

Issue 2:
STR

Didn't have time to write a shorter snippet

#![crate_type = "lib"]
#![feature(associated_types, lang_items, unboxed_closures)]
#![no_std]

use Option::{None, Some};

trait Iterator {
type Item;

fn next(&mut self) -> Option<Self::Item>;
}

trait DoubleEndedIterator: Iterator {
fn next_back(&mut self) -> Option< <Self as Iterator>::Item>;
}

struct Rev<I>(I);

impl<I> Iterator for Rev<I> where I: DoubleEndedIterator {
// forgot this!
//type Item = <I as Iterator>::Item;

fn next(&mut self) -> Option< <I as Iterator>::Item> {
self.0.next_back()
}
}

#[lang = "copy"] trait Copy {}
#[lang = "sized"] trait Sized {}

enum Option<T> {
None,
Some(T),
}

#[lang = "fn_mut"]
trait FnMut<Args, Result> {
extern "rust-call" fn call_mut(&mut self, Args) -> Result;
}

Output

iter.rs:23:5: 25:6 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 38 }:Rev<I>.Iterator, substs=Substs[types=[[_];[];[]], regions=[[];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(I, Sized))),depth=1), Obligation(predicate=Binder(TraitPredicate(TraitRef(I, DoubleEndedIterator))),depth=1)];[];[]])` did not contain projection for `Obligation(predicate=<Rev<I> as TraitRef(Rev<I>, Iterator)>::Item,depth=0)`
iter.rs:23 fn next(&mut self) -> Option< <I as Iterator>::Item> {
iter.rs:24 self.0.next_back()
iter.rs:25 }
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /root/rust/src/libsyntax/diagnostic.rs:123

stack backtrace:
1: 0x7fddb1e70120 - sys::backtrace::write::h3fe61c98bf398fe8P8s
2: 0x7fddb1e8fef0 - failure::on_fail::h55da319a91ee267cEpz
3: 0x7fddb1e05b40 - rt::unwind::begin_unwind_inner::h2a51826b093fcd9eJ3y
4: 0x7fddad24b3d0 - rt::unwind::begin_unwind::h3298842058425057001
5: 0x7fddad24b360 - diagnostic::SpanHandler::span_bug::heeaf2edd6daa003fNQF
6: 0x7fddb022acb0 - middle::traits::project::project_type::hcf50d7eec736df9c35P
7: 0x7fddb0222800 - middle::traits::fulfill::process_predicate::h3703aabc133e79cayGP
8: 0x7fddb0221ab0 - middle::traits::fulfill::FulfillmentContext<$u{27}tcx$GT$::select::h827e4d042486e566SzP
9: 0x7fddb00ee7c0 - middle::traits::fulfill::FulfillmentContext<$u{27}tcx$GT$::select_all_or_error::heebbe09eddbd26dfDwP
10: 0x7fddb1510cd0 - check::compare_impl_method::h359a8a44e8f8def4Zfk
11: 0x7fddb14ff0b0 - check::check_item::hfedb86714512d4d8XRj
12: 0x7fddb169d450 - check_crate::unboxed_closure.39783
13: 0x7fddb16981f0 - check_crate::h7446c5344d10b3c1cGx
14: 0x7fddb23a98d0 - driver::phase_3_run_analysis_passes::hb59d2d67157ec124gva
15: 0x7fddb2397fb0 - driver::compile_input::hff9e8d16e3108315vba
16: 0x7fddb24e4900 - thunk::F.Invoke<A,$u{20}R$GT$::invoke::h10803646332669730367
17: 0x7fddb24e36c0 - rt::unwind::try::try_fn::h3820096971255462672
18: 0x7fddb1ef4eb0 - rust_try_inner
19: 0x7fddb1ef4ea0 - rust_try
20: 0x7fddb24e3a10 - thunk::F.Invoke<A,$u{20}R$GT$::invoke::h15250775183210022334
21: 0x7fddb1e7f8d0 - sys::thread::thread_start::h7b82ef93cab3e580K1v
22: 0x7fddaca690c0 - start_thread
23: 0x7fddb1aab2d9 - __clone
24: 0x0 - <unknown>

Version

84f5ad8

cc @nikomatsakis