ICE when trying to instanciate a trait

[tomaka]

Compiling this code triggers an ICE:

fn main() {
    Reader {
        test: 5
    }
}

Message:

ERROR:serialize::ebml::reader: failed to find block with tag 7
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 'explicit failure', /build/buildd/rust-nightly-201407150406~b1ae09e~trusty/src/libserialize/ebml.rs:226

I'm using today's nightly from the PPA.

stack backtrace:
   1:     0x7ff2af64b810 - rt::backtrace::imp::write::h1d607b6e9ef71a13t7p
   2:     0x7ff2af64f070 - <unknown>
   3:     0x7ff2afe2a850 - unwind::begin_unwind_inner::hd89f00e805829b4f40d
   4:     0x7ff2ad90f480 - <unknown>
   5:     0x7ff2ad910120 - ebml::reader::get_doc::hd5db28090d50edb0Oaf
   6:     0x7ff2b0cee520 - metadata::decoder::get_type::h2eb18260543aab541yn
   7:     0x7ff2b04f4510 - middle::ty::lookup_item_type::h92cce6e3087931e2YOS
   8:     0x7ff2b081f190 - <unknown>
   9:     0x7ff2b07f60e0 - <unknown>
  10:     0x7ff2b07f1780 - <unknown>
  11:     0x7ff2b07f14b0 - <unknown>
  12:     0x7ff2b07ea6f0 - middle::typeck::check::check_item::h9edb33bb2f3d6603Kte
  13:     0x7ff2b07f12b0 - middle::typeck::check::check_item_types::h297f8592deb215c0RVd
  14:     0x7ff2b09622b0 - middle::typeck::check_crate::hfd6ee7ca14d835b1UhE
  15:     0x7ff2b0d2f670 - driver::driver::phase_3_run_analysis_passes::h8be1cb97cb0b7e91pIs
  16:     0x7ff2b0d2af10 - driver::driver::compile_input::h50dc2b89a71bba3bqus
  17:     0x7ff2b0de1f50 - <unknown>
  18:     0x7ff2b0de1e60 - <unknown>
  19:     0x7ff2b0df5ca0 - <unknown>
  20:     0x7ff2b0df5a30 - <unknown>
  21:     0x7ff2b2ec5550 - <unknown>
  22:     0x7ff2afe808a0 - rust_try
  23:     0x7ff2afe278e0 - unwind::try::h5ff2dc0ac502895etPd
  24:     0x7ff2afe27640 - task::Task::run::h7ff45aceeafaf8abP0c
  25:     0x7ff2b2ec5340 - <unknown>
  26:     0x7ff2afe298c0 - <unknown>
  27:     0x7ff2af0cb0c0 - start_thread
  28:     0x7ff2afaec2d9 - __clone
  29:                0x0 - <unknown>

This was fixed in #16867 so can be closed now.

@alexcrichton I think this can be simply closed. The test from #16867 seems to cover the exact same scenario modulo cross-crateness of the trait.

[alexcrichton]

Ah yes, thanks!