the compiler unexpectedly panicked when unboxed trait is used in Enum

[hyunsik]

The reproduction code is as the following. DataSet in Plan enum should be enclosed by Box, but I missed it. In this case, rustc should have caused the compilation error as far as I know. But, it causes compiler panic.

pub trait DataSet: Display {
  fn bind(&mut self) -> Void;  
  fn name(&self) -> &str;
...

pub enum Plan {
  From (DataSet),
  Select(Box<Plan>, Vec<Expr>), // params: child, filter in a CNF form
...

pub struct DataFrame<'a> {
  pub ctx : &'a TokamakContext,
  pub plan: Plan
}

pub fn from<'a, T: DataSet + 'a>(&'a self, ds: T) -> DataFrame<'a> {
    DataFrame {ctx: self, plan: Plan::From(ds)}
}

Meta

rustc --version --verbose:

rustc 1.5.0-nightly (206af38e7 2015-10-17)
binary: rustc
commit-hash: 206af38e74ce7fa4b0e781ece7f1067c018c580e
commit-date: 2015-10-17
host: x86_64-unknown-linux-gnu
release: 1.5.0-nightly

Backtrace:

error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
thread 'rustc' panicked at 'Unexpected type returned from struct_tail: common::plan::Plan for ty=common::plan::Plan', ../src/librustc_trans/trans/type_of.rs:385
stack backtrace:
   1:     0x7f0ec0b7ab80 - sys::backtrace::tracing::imp::write::hc9cd4475e839602bcet
   2:     0x7f0ec0b81455 - panicking::log_panic::_<closure>::closure.39375
   3:     0x7f0ec0b80ec5 - panicking::log_panic::h590c92fc0a4ce7d8kex
   4:     0x7f0ec0b45a93 - sys_common::unwind::begin_unwind_inner::h613f56b60805f050g7r
   5:     0x7f0ec0b463f8 - sys_common::unwind::begin_unwind_fmt::h1bc638525cf6f9f1m6r
   6:     0x7f0ec0048f32 - trans::type_of::in_memory_type_of::h861e6ec0299bb850QyN
   7:     0x7f0ec005b667 - trans::type_of::arg_type_of::he94d012163516b74exN
   8:     0x7f0ec0121c4e - trans::type_of::type_of_rust_fn::h58bc5d6bbfb81b978iN
   9:     0x7f0ec0055ace - trans::declare::declare_rust_fn::hca2ab4ed8541921dKrA
  10:     0x7f0ec0083855 - trans::base::register_fn::h4ea61b21d03fafc9KZi
  11:     0x7f0ec007df09 - trans::base::get_item_val::h1e00603cd1bd358ebcj
  12:     0x7f0ec0079f89 - trans::base::trans_item::hf20ffb9e34f45149EQi
  13:     0x7f0ec007ab18 - trans::base::trans_item::hf20ffb9e34f45149EQi
  14:     0x7f0ec0087f94 - trans::base::trans_crate::h7f9be4f55fb77deexCj
  15:     0x7f0ec10568e9 - driver::phase_4_translate_to_llvm::ha38fc904a5b65c96rPa
  16:     0x7f0ec10509f6 - driver::phase_3_run_analysis_passes::_<closure>::closure.21866
  17:     0x7f0ec103251c - middle::ty::context::_<impl>::create_and_enter::create_and_enter::h1581818717133174881
  18:     0x7f0ec102df5d - driver::phase_3_run_analysis_passes::h14363318041318723032
  19:     0x7f0ec100ec4c - driver::compile_input::h7429410b945488fe7ba
  20:     0x7f0ec115d3eb - run_compiler::h9bfa87b2a333b60e0pc
  21:     0x7f0ec115ac76 - boxed::_<impl>::call_box::call_box::h14045816518007926184
  22:     0x7f0ec115a584 - sys_common::unwind::try::try_fn::try_fn::h13580444196100517801
  23:     0x7f0ec0b788a8 - __rust_try
  24:     0x7f0ec0b6d02b - sys_common::unwind::try::inner_try::hbe40bc0f15f0f398O3r
  25:     0x7f0ec115a71e - boxed::_<impl>::call_box::call_box::h3999059919301623319
  26:     0x7f0ec0b7ff23 - sys::thread::_<impl>::new::thread_start::h6db8a86c0e97df0byww
  27:     0x7f0eba2276a9 - start_thread
  28:     0x7f0ec0804eec - clone
  29:                0x0 - <unknown>

[apasel422]

This is a duplicate of #29057 and #16812.