ICE: failed at 't_f should be a trait

[reem]

Backtrace:

Build failed, waiting for other jobs to finish...
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 't_f should be a trait', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/librustc/middle/typeck/check/vtable.rs:571

stack backtrace:
   1:        0x111229115 - rt::backtrace::imp::write::h38c3950ca30819fdNhr
   2:        0x11122c451 - failure::on_fail::h61277a1f47996a75Hyr
   3:        0x1114e2875 - unwind::begin_unwind_inner::h486b778488114bbbb0d
   4:        0x10dbddd3f - unwind::begin_unwind::h15688615720603158913
   5:        0x10e145615 - middle::typeck::check::vtable::search_for_vtable::hc93570436a21afefjeO
   6:        0x10e14233a - middle::typeck::check::vtable::lookup_vtables_for_param::closure.131025
   7:        0x10e10ee08 - middle::ty::each_bound_trait_and_supertraits::hfe5d3b17da6a6c737NK
   8:        0x10e14146b - middle::typeck::check::vtable::lookup_vtables_for_param::he603570923768e82xIN
   9:        0x10e13f293 - middle::typeck::check::vtable::lookup_vtables::h5d9fd5c00b20dc3aACN
  10:        0x10e14b0ad - middle::typeck::check::vtable::early_resolve_expr::h3ddc282e97fd4c73QxO
  11:        0x10e152006 - visit::walk_expr::h15470876899639569448
  12:        0x10e1538b3 - middle::typeck::check::vtable::resolve_in_block::hfae6e84472c1170eCkP
  13:        0x10e1a8128 - middle::typeck::check::check_bare_fn::h123933ec99e6357bdnW
  14:        0x10e1a0dfd - middle::typeck::check::check_item::h2377dab6eb6d14b8W2W
  15:        0x10e1a7efd - middle::typeck::check::check_item_types::hfe659ac64d4816b6cmW
  16:        0x10dbfbb86 - util::common::time::h3975291496971898732
  17:        0x10e3bad58 - middle::typeck::check_crate::hcb694c948ab679e2CYo
  18:        0x10e4770ba - driver::driver::phase_3_run_analysis_passes::h4f6e88a9cc5d1c8fGGD
  19:        0x10e471f8b - driver::driver::compile_input::h6fd531f77f6169fctsD
  20:        0x10e4fcfaa - driver::run_compiler::hb663589ebabe2c20IjH
  21:        0x10e4fb3b6 - driver::main_args::closure.147451
  22:        0x10dc13d6b - task::TaskBuilder<S>::try_future::closure.100018
  23:        0x10dc13c73 - task::TaskBuilder<S>::spawn_internal::closure.99989
  24:        0x10f8b72cd - task::spawn_opts::closure.8473
  25:        0x111544d2c - rust_try_inner
  26:        0x111544d16 - rust_try
  27:        0x1114dfd17 - unwind::try::h513c5138bad9ea23lOd
  28:        0x1114dfb8c - task::Task::run::h87d8d159864e6bc2L0c
  29:        0x10f8b7122 - task::spawn_opts::closure.8412
  30:        0x1114e17ba - thread::thread_start::hb27c396f8741958eSld
  31:     0x7fff904cc899 - _pthread_body
  32:     0x7fff904cc72a - _pthread_struct_init

Could not compile `hyper`.

Unfortunately the source codebase is relatively large, so I'm not sure what else I should post here.

[mdinger]

Could you make a branch with the bug and post a link to it?

[reem]

https://github.com/reem/hyper branch is ice

[mdinger]

Could #16562 be similar? Fix at PR #16912.

[mahkoh]

Needs a better title.

[ghost]

We're missing a reduced test case and the stack trace points to #16562 so accordingly, I am going to close this as a dupe thereof.