Issue 1:
Versions:

$ rustc --version
rustc 0.11.0-pre (11aa731 2014-05-23 14:56:24 -0700)
host: x86_64-unknown-linux-gnu
$ uname -a
Linux test 3.13-1-amd64 #1 SMP Debian 3.13.10-1 (2014-04-15) x86_64 GNU/Linux

Code to reproduce the ICE:

fn test(a: &Vec<u8>) {
print!("{}", a.len());
}

pub fn main() {
let data = vec!();
test(&data);
}

Compilation output (assuming code is in test.rs):

$ RUST_BACKTRACE=1 rustc -g test.rs
test.rs:1:1: 1:1 error: internal compiler error: debuginfo::set_members_of_composite_type() - Already completed forward declaration re-encountered.
test.rs:1 fn test(a: &Vec<u8>) {
^
note: the compiler hit an unexpected failure path. 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
task 'rustc' failed at 'Box<Any>', /tmp/rust/src/libsyntax/diagnostic.rs:106
stack backtrace:
1: 0x7f6088d547b0 - rt::backtrace::imp::write::h91511e92fbebf61dJSy::v0.11.0.pre
2: 0x7f6088cd4900 - rt::unwind::begin_unwind_inner::hc6a3eade6662bd0cRsy::v0.11.0.pre
3: 0x7f60876d4cb0 - rt::unwind::begin_unwind::h14424584252031250192::v0.11.0.pre
4: 0x7f60876d4be0 - diagnostic::SpanHandler::span_bug::hbb40ab336641d6bcoUb::v0.11.0.pre
5: 0x7f6089823d00 - driver::session::Session::span_bug::hbc579a9c1652b4dcWQk::v0.11.0.pre
6: 0x7f608992a540 - middle::trans::debuginfo::set_members_of_composite_type::ha39f45d6f9c0cb39stB::v0.11.0.pre
7: 0x7f6089928e50 - middle::trans::debuginfo::RecursiveTypeDescription::finalize::h0fe21aef99d3e1c0I8A::v0.11.0.pre
8: 0x7f608991d440 - middle::trans::debuginfo::type_metadata::h98963d42bb116c2fCVB::v0.11.0.pre
9: 0x7f608991d440 - middle::trans::debuginfo::type_metadata::h98963d42bb116c2fCVB::v0.11.0.pre
10: 0x7f6089932ee0 - middle::trans::debuginfo::vec_slice_metadata::h5b5525bc44b17f0dCKB::v0.11.0.pre
11: 0x7f608991d440 - middle::trans::debuginfo::type_metadata::h98963d42bb116c2fCVB::v0.11.0.pre
12: 0x7f6089921730 - middle::trans::debuginfo::declare_local::h3f3d7f3d971eec2bBLA::v0.11.0.pre
13: 0x7f6089920a10 - middle::trans::debuginfo::create_local_var_metadata::closure.63979
14: 0x7f6089d15cc0 - middle::pat_util::pat_bindings::closure.76254
15: 0x7f608771bcd0 - ast_util::walk_pat::h73d09c5bbd81fc4aBNv::v0.11.0.pre
16: 0x7f60897fbbd0 - middle::trans::controlflow::trans_stmt::hebe30cb187b2a930B2a::v0.11.0.pre
17: 0x7f60897fdcb0 - middle::trans::controlflow::trans_block::hc64c9e56aa358790I7a::v0.11.0.pre
18: 0x7f608983e730 - middle::trans::expr::trans_rvalue_dps_unadjusted::h9c3393158ea8f3e88hf::v0.11.0.pre
19: 0x7f60897fd5a0 - middle::trans::expr::trans_into::h6b67f346e56d2aaagse::v0.11.0.pre
20: 0x7f60898ee990 - middle::trans::_match::trans_match_inner::he680468c7e8edd8bk7s::v0.11.0.pre
21: 0x7f608983e730 - middle::trans::expr::trans_rvalue_dps_unadjusted::h9c3393158ea8f3e88hf::v0.11.0.pre
22: 0x7f60897fd5a0 - middle::trans::expr::trans_into::h6b67f346e56d2aaagse::v0.11.0.pre
23: 0x7f60897fc780 - middle::trans::controlflow::trans_stmt_semi::h95ab3162fcdb8669P6a::v0.11.0.pre
24: 0x7f60897fbbd0 - middle::trans::controlflow::trans_stmt::hebe30cb187b2a930B2a::v0.11.0.pre
25: 0x7f60897fdcb0 - middle::trans::controlflow::trans_block::hc64c9e56aa358790I7a::v0.11.0.pre
26: 0x7f60898bb6c0 - middle::trans::base::trans_closure::hd893efe09250c8a3Php::v0.11.0.pre
27: 0x7f60897c6df0 - middle::trans::base::trans_fn::h02396ab03da5196a5pp::v0.11.0.pre
28: 0x7f60897c1110 - middle::trans::base::trans_item::h4715e8b19ebc5b3eCBp::v0.11.0.pre
29: 0x7f60898ca380 - middle::trans::base::trans_crate::h97a887f98edb0d3dpoq::v0.11.0.pre
30: 0x7f608a0a1430 - driver::driver::phase_4_translate_to_llvm::h29f793bbb3691a0c01j::v0.11.0.pre
31: 0x7f608a096b40 - driver::driver::compile_input::hf7a007097756b7ceBJj::v0.11.0.pre
32: 0x7f608a160180 - driver::run_compiler::h6c18401fac048ee4umm::v0.11.0.pre
33: 0x7f608a1600a0 - driver::main_args::closure.93487
34: 0x7f608a174b50 - driver::monitor::closure.94559
35: 0x7f608a170070 - task::TaskBuilder::try::closure.94322
36: 0x7f608926c970 - task::spawn_opts::closure.7801
37: 0x7f6088d4e6e0 - rt::task::Task::run::closure.25256
38: 0x7f6088dadab0 - rust_try
39: 0x7f6088d4e630 - rt::task::Task::run::h9a36fd2f34280279uhw::v0.11.0.pre
40: 0x7f608926c720 - task::spawn_opts::closure.7774
41: 0x7f6088d52b60 - rt::thread::thread_start::h057270a612f2c73020w::v0.11.0.pre
42: 0x7f60867fdfa0 - start_thread
43: 0x7f608899cbe9 - __clone
44: 0x0 - <unknown>

$

This might be related to issue #14385.

Issue 2:
servo/src/support/glfw/glfw-rs/src/lib/lib.rs:1:1: 1:1 error: internal compiler error: debuginfo::set_members_of_composite_type() - Already completed forward declaration re-encountered.
...
task 'rustc' failed at 'Box<Any>', /home/travis/build/Manishearth/rust/src/libsyntax/diagnostic.rs:99

This seems similar to the already-fixed issue #11083

Note: I'm using a Rust snapshot that I generated on a different system (with the same DEFAULT_TARGET as mine)

cc @michaelwoerister