ICE: Unexpected tail in unsized_info_ty

[jonhoo]

The following code causes a compiler panic:

pub trait A<T> {}

pub enum C<T> {
    A(A<T>),
}

fn main() {
    let _: Option<Box<C<&str>>> = None;
}

$ rustup run nightly rustc x.rs
error: internal compiler error: ../src/librustc_trans/type_of.rs:178: Unexpected tail in unsized_info_ty: C<&str> for ty=C<&str>
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
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', ../src/libsyntax/errors/mod.rs:584
stack backtrace:
   1:     0x7f547094161f - std::sys::backtrace::tracing::imp::write::h6528da8103c51ab9
   2:     0x7f547094f20b - std::panicking::default_hook::_$u7b$$u7b$closure$u7d$$u7d$::hbe741a5cc3c49508
   3:     0x7f547094eda8 - std::panicking::default_hook::he0146e6a74621cb4
   4:     0x7f547091516e - std::panicking::rust_panic_with_hook::h983af77c1a2e581b
   5:     0x7f546bc19e07 - std::panicking::begin_panic::hf9f206df23a555af
   6:     0x7f546bc1976e - syntax::errors::Handler::bug::hd25802f012f6858b
   7:     0x7f546ce8d854 - rustc::session::opt_span_bug_fmt::_$u7b$$u7b$closure$u7d$$u7d$::h083e19915ee66466
   8:     0x7f546ce8d65d - rustc::session::opt_span_bug_fmt::h157ddeb5b4622d22
   9:     0x7f546cea8036 - rustc::session::bug_fmt::h166f9667daf4dd54
  10:     0x7f546e491493 - rustc_trans::type_of::unsized_info_ty::hf0d5468d19bde7c2
  11:     0x7f546e33d1fc - rustc_trans::type_of::sizing_type_of::hf1ac5f8b6f66decc
  12:     0x7f546e345829 - _<collections..vec..Vec<T> as core..iter..traits..FromIterator<T>>::from_iter::hbabd995607a71cd2
  13:     0x7f546e342f68 - rustc_trans::adt::mk_struct::h66b7982c2b9de54e
  14:     0x7f546e340134 - rustc_trans::adt::represent_type::h04b5e656cc36c330
  15:     0x7f546e3f662d - rustc_trans::consts::const_expr_unadjusted::h7fee3ce2f8dec095
  16:     0x7f546e3f2104 - rustc_trans::consts::const_expr::h89b51f911278b3c4
  17:     0x7f546e3f355e - rustc_trans::consts::get_const_expr_as_global::h6bfb11a3176d89fa
  18:     0x7f546e3c6d02 - rustc_trans::expr::trans::hae685ae3f283bfbf
  19:     0x7f546e35e65e - rustc_trans::base::init_local::hbbeb45fbf0b21a8a
  20:     0x7f546e37435b - rustc_trans::controlflow::trans_block::h7ec6b213337f773e
  21:     0x7f546e36f338 - rustc_trans::base::trans_closure::h9e96f7e9279dd729
  22:     0x7f546e374e83 - rustc_trans::base::trans_fn::ha453f4075c16fe7d
  23:     0x7f546e37f10e - rustc_trans::base::trans_item::hca2904a0eb6b2a6f
  24:     0x7f546e3977b3 - _<rustc_trans..base..TransItemsWithinModVisitor<'a, 'tcx> as rustc..hir..intravisit..Visitor<'v>>::visit_item::hc86f557d139a067e
  25:     0x7f546e3880e7 - rustc_trans::base::trans_crate::h999c47a06d45abea
  26:     0x7f5470e93eff - rustc_driver::driver::phase_4_translate_to_llvm::had910d0e745bc40f
  27:     0x7f5470e91d8d - rustc_driver::driver::compile_input::_$u7b$$u7b$closure$u7d$$u7d$::hf187cb470aad2bf2
  28:     0x7f5470e8e4ed - rustc_driver::driver::phase_3_run_analysis_passes::_$u7b$$u7b$closure$u7d$$u7d$::hd565ad56c5876a16
  29:     0x7f5470e87cb9 - rustc::ty::context::TyCtxt::create_and_enter::habef58c7230d34f9
  30:     0x7f5470e510af - rustc_driver::driver::compile_input::hfd60b020f6d0208d
  31:     0x7f5470e3d0a4 - rustc_driver::run_compiler::h884d01d12eb76bbb
  32:     0x7f5470e3a17e - std::panicking::try::call::hd72cf79141f67e60
  33:     0x7f547095d6cb - __rust_try
  34:     0x7f547095d66e - __rust_maybe_catch_panic
  35:     0x7f5470e3ac64 - _<F as alloc..boxed..FnBox<A>>::call_box::h589d2091babf223a
  36:     0x7f547094d334 - std::sys::thread::Thread::new::thread_start::h9c883b6d445ece46
  37:     0x7f546839f473 - start_thread
  38:     0x7f547059c69c - clone
  39:                0x0 - <unknown>

Meta

$ rustup run nightly rustc --version --verbose
rustc 1.11.0-nightly (ec872dc8a 2016-06-07)
binary: rustc
commit-hash: ec872dc8a3f008299ca1508105ee064d1f0f0367
commit-date: 2016-06-07
host: x86_64-unknown-linux-gnu
release: 1.11.0-nightly

[apasel422]

Duplicate of #32765.