Internal compiler error in metadata::tydecode::parse_def_id related to unboxes closures

[TethysSvensson]

$ apt-cache policy rust-nightly && rustc -v verbose
rust-nightly:
  Installed: 201408270406~e61ec99~utopic
  Candidate: 201408270406~e61ec99~utopic
  Version table:
 *** 201408270406~e61ec99~utopic 0
        500 http://ppa.launchpad.net/hansjorg/rust/ubuntu/ utopic/main amd64 Packages
        100 /var/lib/dpkg/status
rustc 0.12.0-pre
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-unknown-linux-gnu
release: 0.12.0-pre
$ cat foo.rs
#![crate_name = "foo"]
#![crate_type = "rlib"]

#![feature(unboxed_closures)]

pub fn bar<T>(val: &mut Box<FnOnce<(), T>>) {
  *val = (box |:| fail!()) as Box<FnOnce<(), T>>;
}

$ cat main.rs 
extern crate foo;

fn main() {
  foo::bar::<uint>(fail!());
}
$ rustc foo.rs && echo done && RUST_BACKTRACE=1 rustc -L . main.rs
done
error: internal compiler error: unexpected failure
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 'internal error: parse_def_id: id expected, found
&[50u8, 53u8, 101u8, 199u8, 16u8, 0u8, 0u8, 27u8, 196u8, 136u8, 0u8, 0u8, 0u8,
0u8, 0u8, 0u8, 0u8, 24u8, 197u8, 16u8, 0u8, 0u8, 12u8, 154u8, 16u8, 0u8, 0u8,
7u8, 126u8, 107u8, 48u8, 58u8, 50u8, 53u8, 101u8, 199u8, 16u8, 0u8, 0u8, 26u8,
196u8, 136u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 25u8, 197u8, 16u8, 0u8, 0u8,
11u8, 154u8, 16u8, 0u8, 0u8, 6u8, 107u8, 48u8, 58u8, 50u8, 53u8, 101u8, 201u8,
16u8, 0u8, 0u8, 26u8, 196u8, 136u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 25u8,
197u8, 16u8, 0u8, 0u8, 11u8, 147u8, 16u8, 0u8, 0u8, 6u8, 148u8, 132u8, 0u8,
0u8, 0u8, 0u8, 214u8, 16u8, 0u8, 0u8, 44u8, 196u8, 136u8, 0u8, 0u8, 0u8, 0u8,
0u8, 0u8, 0u8, 25u8, 197u8, 16u8, 0u8, 0u8, 29u8, 155u8, 139u8, 67u8, 97u8,
112u8, 116u8, 117u8, 114u8, 101u8, 77u8, 111u8, 100u8, 101u8, 144u8, 16u8, 0u8,
0u8, 11u8, 145u8, 132u8, 0u8, 0u8, 0u8, 0u8, 146u8, 16u8, 0u8, 0u8, 0u8, 212u8,
16u8, 0u8, 0u8, 86u8, 196u8, 136u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 25u8,
197u8, 16u8, 0u8, 0u8, 71u8, 154u8, 16u8, 0u8, 0u8, 30u8, 110u8, 109u8, 38u8,
116u8, 46u8, 91u8, 50u8, 53u8]',
/build/buildd/rust-nightly-201408270406~e61ec99~utopic/src/librustc/metadata/tydecode.rs:583

stack backtrace:
   1:     0x7f03c197e570 - rt::backtrace::imp::write::h7ecc632a9b3f8170c0q
   2:     0x7f03c1981760 - <unknown>
   3:     0x7f03c2168950 - unwind::begin_unwind_inner::he71f311595519d03Zie
   4:     0x7f03c21685f0 - unwind::begin_unwind_fmt::h08ab7f9fdf4ed6ecpge
   5:     0x7f03c2d39f40 - metadata::tydecode::parse_def_id::h58b712d2d6177e083xp
   6:     0x7f03c2d38c30 - <unknown>
   7:     0x7f03c2d341f0 - <unknown>
   8:     0x7f03c2d341f0 - <unknown>
   9:     0x7f03c26bc820 - metadata::tydecode::parse_ty_data::hdf484fc7b2992be41wn
  10:     0x7f03c26bda80 - <unknown>
  11:     0x7f03c26bc5e0 - <unknown>
  12:     0x7f03c2699450 - middle::astencode::reader..Decoder<'a>.rbml_decoder_decoder_helpers::read_ty::hed6189176e179eaarHe
  13:     0x7f03c26d7200 - <unknown>
  14:     0x7f03c0b7b2e0 - reader::docs::h1ca92fae2366102b2Ua
  15:     0x7f03c25772e0 - middle::astencode::decode_inlined_item::h6909096d11b0b7dan3c
  16:     0x7f03c27addb0 - <unknown>
  17:     0x7f03c2ea8360 - <unknown>
  18:     0x7f03c2d623d0 - metadata::decoder::maybe_get_item_ast::hdd02c275a9b40253hut
  19:     0x7f03c28f22a0 - middle::trans::inline::maybe_instantiate_inline::hf570f206c42708ffTyX
  20:     0x7f03c29410a0 - <unknown>
  21:     0x7f03c29135c0 - middle::trans::callee::trans_call_inner::h10aebb5fe7685fdaLD1
  22:     0x7f03c2940e30 - middle::trans::callee::trans_call::hc4f2c9ea0dad7130Qx1
  23:     0x7f03c294fc60 - <unknown>
  24:     0x7f03c2909dd0 - middle::trans::expr::trans_into::h63efa240a252a4b9js2
  25:     0x7f03c2909280 - middle::trans::controlflow::trans_stmt_semi::hab7df555c62b5a36dlY
  26:     0x7f03c2908950 - middle::trans::controlflow::trans_stmt::h2e9e6b84acdd95beWgY
  27:     0x7f03c290a370 - middle::trans::controlflow::trans_block::hef69e6e8a650479d7lY
  28:     0x7f03c29bfd00 - middle::trans::base::trans_closure::h7b69e84eff2769876xe
  29:     0x7f03c28fada0 - middle::trans::base::trans_fn::h19628e9480b57bbaTJe
  30:     0x7f03c28f60e0 - middle::trans::base::trans_item::h699a0ee17313c445T1e
  31:     0x7f03c29ca9c0 - middle::trans::base::trans_crate::hab4da120219fc0d5kWf
  32:     0x7f03c2d9c480 - driver::driver::phase_4_translate_to_llvm::h070ebeccefe401090yy
  33:     0x7f03c2d93e30 - driver::driver::compile_input::hbae99ff27dbd49ferby
  34:     0x7f03c2e25c50 - <unknown>
  35:     0x7f03c2e25b60 - <unknown>
  36:     0x7f03c2e37de0 - <unknown>
  37:     0x7f03c2e37be0 - <unknown>
  38:     0x7f03c38745f0 - <unknown>
  39:     0x7f03c21c11d0 - <unknown>
  40:     0x7f03c21c11c0 - rust_try
  41:     0x7f03c2165f80 - unwind::try::hcf3a6c26a049b912f7d
  42:     0x7f03c2165d40 - task::Task::run::hb31a60d7e6df8450zdd
  43:     0x7f03c3874350 - <unknown>
  44:     0x7f03c2167b40 - <unknown>
  45:     0x7f03c14150c0 - start_thread
  46:     0x7f03c1e2f359 - __clone
  47:                0x0 - <unknown>

[bkoropoff]

This example now gives me the panic from #18378, which occurs slightly later during decoding.

This bug may have been accidentally fixed at some point, which exposed #18378. I think this just needs a test once the other crate metadata bugs have been fixed.