Issue 1:
➜ matrix-rs git:(master) ✗ RUST_BACKTRACE=1 cargo build --verbose
Fresh rustc-serialize v0.2.4
Fresh num v0.1.5
Compiling matrix-rs v0.0.1 (file:///home/rvlander/CloudStation/WIP/matrix-rs)
Running `rustc /home/rvlander/CloudStation/WIP/matrix-rs/src/lib.rs --crate-name matrix-rs --crate-type lib -g -C metadata=911cbf09ca74d9fa -C extra-filename=-911cbf09ca74d9fa --out-dir /home/rvlander/CloudStation/WIP/matrix-rs/target --emit=dep-info,link -L /home/rvlander/CloudStation/WIP/matrix-rs/target -L /home/rvlander/CloudStation/WIP/matrix-rs/target/deps --extern num=/home/rvlander/CloudStation/WIP/matrix-rs/target/deps/libnum-99d6507e3aad728a.rlib`
/home/rvlander/CloudStation/WIP/matrix-rs/src/matrix/dense_matrix.rs:54:1: 58:2 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 1042 }:matrix::dense_matrix::DenseMatrix<T>.Add, substs=Substs[types=[[_];[];[]], regions=[[];[];[]]], nested=[[Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Sized))),depth=1), Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::kinds::Copy))),depth=1), Obligation(predicate=Binder(TraitPredicate(TraitRef(T, core::ops::Add))),depth=1)];[];[]])` did not contain projection for `Obligation(predicate=<matrix::dense_matrix::DenseMatrix<T> as TraitRef(matrix::dense_matrix::DenseMatrix<T>, core::ops::Add)>::Output,depth=0)`
/home/rvlander/CloudStation/WIP/matrix-rs/src/matrix/dense_matrix.rs:54 impl <T: Add<T> + Copy> Add for DenseMatrix<T> {
/home/rvlander/CloudStation/WIP/matrix-rs/src/matrix/dense_matrix.rs:55 fn add(self, rhs: DenseMatrix<T>) -> DenseMatrix<T> {
/home/rvlander/CloudStation/WIP/matrix-rs/src/matrix/dense_matrix.rs:56 self.__add(rhs)
/home/rvlander/CloudStation/WIP/matrix-rs/src/matrix/dense_matrix.rs:57 }
/home/rvlander/CloudStation/WIP/matrix-rs/src/matrix/dense_matrix.rs:58 }
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: 0x7f7c86e9b920 - sys::backtrace::write::h36422e877a8b3158yQs
2: 0x7f7c86ec1650 - failure::on_fail::hde5005d61795902da3y
3: 0x7f7c86e274a0 - rt::unwind::begin_unwind_inner::ha0668a3a9d73b9a7RHy
4: 0x7f7c81d00af0 - rt::unwind::begin_unwind::h9147230717703493418
5: 0x7f7c81d00a80 - diagnostic::SpanHandler::span_bug::hee7de6e88971705bDFF
6: 0x7f7c851fbc70 - middle::traits::project::project_type::ha3169b6d00cba236CYP
7: 0x7f7c851f8dd0 - middle::traits::project::opt_normalize_projection_type::h52e80e1c888609adFQP
8: 0x7f7c851e6890 - middle::traits::project::normalize_projection_type::had1d9d27edaeb68fgPP
9: 0x7f7c851fa270 - middle::traits::project::AssociatedTypeNormalizer<'a, 'b, 'tcx>.TypeFolder<'tcx>::fold_ty::h8977cf1010cf2ef8RNP
10: 0x7f7c864b7990 - middle::ty_fold::TypeFolder::fold_trait_ref::h15244371943192340039
11: 0x7f7c864b85c0 - middle::ty_fold::VecPerParamSpace<T>.TypeFoldable<'tcx>::fold_with::h3029018912722243389
12: 0x7f7c864d3b40 - check::FnCtxt<'a, 'tcx>::instantiate_bounds::haf69ce16fdf22227Nul
13: 0x7f7c864ec870 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::check_impl::closure.30018
14: 0x7f7c864e8ce0 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::with_fcx::h0df2a1129da2a633Hfi
15: 0x7f7c864ef760 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::hc72c9294b1b3f21ftoi
16: 0x7f7c864f15c0 - visit::walk_mod::h2450081392115226323
17: 0x7f7c864ef760 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::hc72c9294b1b3f21ftoi
18: 0x7f7c864f15c0 - visit::walk_mod::h2450081392115226323
19: 0x7f7c864ef760 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::hc72c9294b1b3f21ftoi
20: 0x7f7c866ddbd0 - check_crate::unboxed_closure.40283
21: 0x7f7c866d8820 - check_crate::h4ba306a17295b431iux
22: 0x7f7c873dc600 - driver::phase_3_run_analysis_passes::h56810662503f92d8Sva
23: 0x7f7c873caaa0 - driver::compile_input::h8d0abf631800220evba
24: 0x7f7c87496070 - thunk::F.Invoke<A, R>::invoke::h13263903969514368718
25: 0x7f7c87494e20 - rt::unwind::try::try_fn::h2272437873322108176
26: 0x7f7c86f258b0 - rust_try_inner
27: 0x7f7c86f258a0 - rust_try
28: 0x7f7c87495170 - thunk::F.Invoke<A, R>::invoke::h17236552692728063371
29: 0x7f7c86ead490 - sys::thread::thread_start::hd19c7749b7af23e8EGv
30: 0x7f7c81525250 - start_thread
31: 0x7f7c86ae2219 - clone
32: 0x0 - <unknown>

Could not compile `matrix-rs`.

Caused by:
Process didn't exit successfully: `rustc /home/rvlander/CloudStation/WIP/matrix-rs/src/lib.rs --crate-name matrix-rs --crate-type lib -g -C metadata=911cbf09ca74d9fa -C extra-filename=-911cbf09ca74d9fa --out-dir /home/rvlander/CloudStation/WIP/matrix-rs/target --emit=dep-info,link -L /home/rvlander/CloudStation/WIP/matrix-rs/target -L /home/rvlander/CloudStation/WIP/matrix-rs/target/deps --extern num=/home/rvlander/CloudStation/WIP/matrix-rs/target/deps/libnum-99d6507e3aad728a.rlib` (status=101)

Issue 2:
This 3-liner crashes rustc:

struct CrashIt;
impl Iterator for CrashIt { }
fn main() { }

My original code did a lot more than that, but I tried to create the minimal repro case.

$ rustc --version --verbose
rustc 0.13.0-nightly (c6c786671 2015-01-04 00:50:59 +0000)
binary: rustc
commit-hash: c6c786671d692d7b13c2e5c68a53001327b4b125
commit-date: 2015-01-04 00:50:59 +0000
host: x86_64-unknown-linux-gnu
release: 0.13.0-nightly

$ RUST_BACKTRACE=1 rustc src/main.rs
src/main.rs:2:1: 2:30 error: internal compiler error: impl `VtableImpl(impl_def_id=DefId { krate: 0, node: 7 }:CrashIt.Iterator, substs=Substs[types=[[];[];[]], regions=[[];[];[]]], nested=[[];[];[]])` did not contain projection for `Obligation(predicate=<CrashIt as TraitRef(CrashIt, core::iter::Iterator)>::Item,depth=0)`
src/main.rs:2 impl Iterator for CrashIt { }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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: 0x7fbff73562d0 - sys::backtrace::write::h8532e701ef86014f4it
2: 0x7fbff737bb00 - failure::on_fail::h7532e1f79d134d5dzvz
3: 0x7fbff72e11c0 - rt::unwind::begin_unwind_inner::h97b151606151d62deaz
4: 0x7fbff218ec60 - rt::unwind::begin_unwind::h15809447133099964284
5: 0x7fbff218ebf0 - diagnostic::SpanHandler::span_bug::he8142ababcc30c39DFF
6: 0x7fbff568de70 - middle::traits::project::project_type::h947eece142ef049d52P
7: 0x7fbff568afd0 - middle::traits::project::opt_normalize_projection_type::hb3defb9cc9365d1e8UP
8: 0x7fbff5678ba0 - middle::traits::project::normalize_projection_type::hdc293893275ee559JTP
9: 0x7fbff568c470 - middle::traits::project::AssociatedTypeNormalizer<'a, 'b, 'tcx>.TypeFolder<'tcx>::fold_ty::h801cbd2cdff2eff1kSP
10: 0x7fbff69492e0 - middle::ty_fold::Rc<T>.TypeFoldable<'tcx>::fold_with::h6325524173844043840
11: 0x7fbff6949e90 - middle::ty_fold::VecPerParamSpace<T>.TypeFoldable<'tcx>::fold_with::h13884369302522804796
12: 0x7fbff6965280 - check::FnCtxt<'a, 'tcx>::instantiate_bounds::hed550a9659b70335Oll
13: 0x7fbff697dfc0 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::check_impl::closure.29997
14: 0x7fbff697a430 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::with_fcx::hb1283961ed8977b7Gfi
15: 0x7fbff6980d70 - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>.Visitor<'v>::visit_item::h001ababd87597e37soi
16: 0x7fbff6b6dfe0 - check_crate::unboxed_closure.40162
17: 0x7fbff6b68c30 - check_crate::h19fb6dea5733566ajsx
18: 0x7fbff78a7640 - driver::phase_3_run_analysis_passes::h46b1604d9f9f5633Tva
19: 0x7fbff7895ae0 - driver::compile_input::h68b8602933aad8d7wba
20: 0x7fbff7960eb0 - thunk::F.Invoke<A, R>::invoke::h18029802347644288836
21: 0x7fbff795fc60 - rt::unwind::try::try_fn::h6518866316425934196
22: 0x7fbff73e2400 - rust_try_inner
23: 0x7fbff73e23f0 - rust_try
24: 0x7fbff795ffb0 - thunk::F.Invoke<A, R>::invoke::h15513809553472565307
25: 0x7fbff7367e40 - sys::thread::thread_start::h5ea7ba97235331d5a9v
26: 0x7fbff19b2c20 - start_thread
27: 0x7fbff6f83899 - clone
28: 0x0 - <unknown>