ICE: Unexpected type returned from struct_tail

[ftxqxd]

enum Foo {
    Bar(int, [int]),
}

fn main() {
    // Either of these lines can cause the ICE
    let _x: &(int, [int]);
    let _y: &Foo;
}

Backtrace:

   1:     0x7f2a127e8580 - rt::backtrace::imp::write::h0180e7ded76a3ff2c0q
   2:     0x7f2a127eb770 - failure::on_fail::h3f169393c89b5f90Tlr
   3:     0x7f2a12fd24f0 - unwind::begin_unwind_inner::haeb9517b5061bc86Zie
   4:     0x7f2a133ad670 - unwind::begin_unwind::h17017358962417336117
   5:     0x7f2a13803a20 - middle::ty::unsized_part_of_type::h8eae6d239e9b7af3tnG
   6:     0x7f2a138037c0 - middle::trans::type_of::type_of::type_of_unsize_info::h67819f63aa2acfb5Xh9
   7:     0x7f2a1377b050 - middle::trans::type_of::type_of::h3c89a1738d384c45Ih9
   8:     0x7f2a1377b050 - middle::trans::type_of::type_of::h3c89a1738d384c45Ih9
   9:     0x7f2a137b0860 - middle::trans::base::alloc_ty::h5485998eeb61d023mTd
  10:     0x7f2a13859870 - middle::trans::_match::mk_binding_alloca::h11628361498234501597
  11:     0x7f2a1385bdf0 - middle::trans::_match::store_local::create_dummy_locals::closure.119283
  12:     0x7f2a13681560 - middle::pat_util::pat_bindings::closure.112016
  13:     0x7f2a0ea1ccb0 - ast_util::walk_pat::hc858153057fb5965oRB
  14:     0x7f2a138205f0 - middle::trans::_match::store_local::h9195017fe21b4124A2h
  15:     0x7f2a13772d10 - middle::trans::base::init_local::h5e8a493dc2ae05b1WFd
  16:     0x7f2a13772220 - middle::trans::controlflow::trans_stmt::hf26d5cee55a6056blhY
  17:     0x7f2a13773c40 - middle::trans::controlflow::trans_block::h004dea36138a75c8wmY
  18:     0x7f2a13829560 - middle::trans::base::trans_closure::h655acfc433ac13fevye
  19:     0x7f2a13764670 - middle::trans::base::trans_fn::hf0a444fa9ff43aebiKe
  20:     0x7f2a1375f9b0 - middle::trans::base::trans_item::hda4d4160cb2b58dfi2e
  21:     0x7f2a138341f0 - middle::trans::base::trans_crate::hff0f87c98e6356c8JWf
  22:     0x7f2a13c058d0 - driver::driver::phase_4_translate_to_llvm::h8223ee9d7ab4951cpzy
  23:     0x7f2a13bfd280 - driver::driver::compile_input::hfa4fd95c9e6a2ceeQby
  24:     0x7f2a13c8f0a0 - driver::run_compiler::h32bdccca6ed9465cJIB
  25:     0x7f2a13c8efb0 - driver::main_args::closure.138206
  26:     0x7f2a13ca1240 - task::TaskBuilder<S>::try_future::closure.139324
  27:     0x7f2a13ca1040 - task::TaskBuilder<S>::spawn_internal::closure.139301
  28:     0x7f2a146dcf10 - task::spawn_opts::closure.8369
  29:     0x7f2a1302af90 - rust_try_inner
  30:     0x7f2a1302af80 - rust_try
  31:     0x7f2a12fcfb20 - unwind::try::h03d8d1d4cb0de0c1f7d
  32:     0x7f2a12fcf8e0 - task::Task::run::hafab6bcab45e61e5zdd
  33:     0x7f2a146dcc70 - task::spawn_opts::closure.8315
  34:     0x7f2a12fd16e0 - thread::thread_start::hba588af1f803bb5blCd
  35:     0x7f2a1227f0c0 - start_thread
  36:     0x7f2a12c99359 - __clone
  37:                0x0 - <unknown>

This seems to occur when using a non-struct type that contains an unsized type. This is probably because unsized_part_of_type only handles ty_struct and the base unsized types. This should be extended to handle enums and tuples as well.

[pythonesque]

This is still happening. Does this mean we should avoid using DSTs for complex custom types for now?

[frewsxcv]

Visiting for triage

This is still an issue:

/tmp $ rustc hi.rs
hi.rs:2:9: 2:12 warning: the `int` type is deprecated; use `isize` or a fixed-sized integer
hi.rs:2     Bar(int, [int]),
                ^~~
hi.rs:2:9: 2:12 help: add #![feature(int_uint)] to the crate attributes to silence this warning
hi.rs:2     Bar(int, [int]),
                ^~~
hi.rs:2:15: 2:18 warning: the `int` type is deprecated; use `isize` or a fixed-sized integer
hi.rs:2     Bar(int, [int]),
                      ^~~
hi.rs:2:15: 2:18 help: add #![feature(int_uint)] to the crate attributes to silence this warning
hi.rs:2     Bar(int, [int]),
                      ^~~
hi.rs:7:15: 7:18 warning: the `int` type is deprecated; use `isize` or a fixed-sized integer
hi.rs:7     let _x: &(int, [int]);
                      ^~~
hi.rs:7:15: 7:18 help: add #![feature(int_uint)] to the crate attributes to silence this warning
hi.rs:7     let _x: &(int, [int]);
                      ^~~
hi.rs:7:21: 7:24 warning: the `int` type is deprecated; use `isize` or a fixed-sized integer
hi.rs:7     let _x: &(int, [int]);
                            ^~~
hi.rs:7:21: 7:24 help: add #![feature(int_uint)] to the crate attributes to silence this warning
hi.rs:7     let _x: &(int, [int]);
                            ^~~
hi.rs:2:5: 2:20 warning: variant is never used: `Bar`, #[warn(dead_code)] on by default
hi.rs:2     Bar(int, [int]),
            ^~~~~~~~~~~~~~~
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. 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
thread 'rustc' panicked at 'unsized_part_of_type failed even though ty is unsized', /Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/src/librustc_trans/trans/common.rs:166

stack backtrace:
   1:        0x10cdf4ef7 - sys::backtrace::write::h88d0d05790f5fe63uvy
   2:        0x10ce1b1d2 - failure::on_fail::h254ebaa74a16f795dOF
   3:        0x10cd70828 - rt::unwind::begin_unwind_inner::ha4f653fd236db381FvF
   4:        0x10948a235 - rt::unwind::begin_unwind::h12190706954857531769
   5:        0x10955e7f1 - trans::common::unsized_part_of_type::heb51b171ecadcb48HMk
   6:        0x10958f3b2 - trans::type_of::type_of::type_of_unsize_info::hd1a63e34e2e99b94A2o
   7:        0x1094e2e81 - trans::type_of::type_of::h2372af414ad01c3ag2o
   8:        0x1095114fd - trans::base::alloc_ty::h3d6cf8c39435c8c2yut
   9:        0x1095d95a5 - ast_util::walk_pat::walk_pat_::h12916028195929177049
  10:        0x1094d763f - trans::base::init_local::hfb21acfe815478f3Ggt
  11:        0x1094d8933 - trans::controlflow::trans_block::h924ca481d4b4516asae
  12:        0x1095a486d - trans::base::trans_closure::h818341d4fc835178E5t
  13:        0x1094c45d6 - trans::base::trans_fn::h13435eb2cf011516Ogu
  14:        0x1094bf723 - trans::base::trans_item::hd9986468b8457cd3fFu
  15:        0x1095aab7c - trans::base::trans_crate::h3c7ea32f1a6ebc96ZBv
  16:        0x109360757 - driver::phase_4_translate_to_llvm::h2222bdf86d2278693Oa
  17:        0x10933c772 - driver::compile_input::h024fc27312c2cbcbCba
  18:        0x10940f6fe - run_compiler::h655f217f5987c6497ac
  19:        0x10940c6ef - thunk::F.Invoke<A, R>::invoke::h3444412781138926669
  20:        0x10940b380 - rt::unwind::try::try_fn::h12649063132436107851
  21:        0x10ce923c9 - rust_try_inner
  22:        0x10ce923b6 - rust_try
  23:        0x10940ba40 - thunk::F.Invoke<A, R>::invoke::h6921957054689317792
  24:        0x10ce057d3 - sys::thread::thread_start::h6219f4f9fd58602fhDB
  25:     0x7fff9201f268 - _pthread_body
  26:     0x7fff9201f1e5 - _pthread_body

[tomjakubowski]

ICE also happens with a tupled trait object:

fn main() {
    let x: &(Clone, Iterator) = panic!();
}

error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. 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
thread 'rustc' panicked at 'unsized_part_of_type failed even though ty is unsized', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/librustc_trans/trans/common.rs:166

stack backtrace:
   1:     0x7f197e3b3750 - sys::backtrace::write::h49b06c4e5fa1765dZTA
   2:     0x7f197e3d83e0 - failure::on_fail::h128a61ca90111ec2JFJ
   3:     0x7f197e330350 - rt::unwind::begin_unwind_inner::h142cc6242e7988934jJ
   4:     0x7f197d002e90 - rt::unwind::begin_unwind::h13556005847138426690
   5:     0x7f197d0dc3e0 - trans::common::unsized_part_of_type::h4971bfd82c960f177Sk
   6:     0x7f197d10c5e0 - trans::type_of::type_of::type_of_unsize_info::hc9a1771493b5585eB9o
   7:     0x7f197d05fd20 - trans::type_of::type_of::h45cc5a0ffa907939h9o
   8:     0x7f197d08ef50 - trans::base::alloc_ty::h23dd60deb6e81842ODt
   9:     0x7f197d1563c0 - trans::_match::mk_binding_alloca::h10681521704565058413
  10:     0x7f197d053f30 - trans::base::init_local::hca973ce50444bab8Cpt
  11:     0x7f197d054ea0 - trans::controlflow::trans_block::hfb3d01e31adc3da5Qee
  12:     0x7f197d120030 - trans::base::trans_closure::hd99a1fe118eadd85ofu
  13:     0x7f197d040670 - trans::base::trans_fn::hb1bc39659fd54f79Equ
  14:     0x7f197d03b6f0 - trans::base::trans_item::hf71bcbd6c9a9283ftPu
  15:     0x7f197d1275f0 - trans::base::trans_crate::h3465dd947f56ed22NMv
  16:     0x7f197e9e80e0 - driver::phase_4_translate_to_llvm::h130c1ed11c0c6b37wPa
  17:     0x7f197e9c1190 - driver::compile_input::ha0cf61571709f853Eba
  18:     0x7f197ea922b0 - run_compiler::h331ebfa0d68f5ee75bc
  19:     0x7f197ea90910 - thunk::F.Invoke<A, R>::invoke::h10527493330292840218
  20:     0x7f197ea8f800 - rt::unwind::try::try_fn::h13426443671359034537
  21:     0x7f197e444a70 - rust_try_inner
  22:     0x7f197e444a60 - rust_try
  23:     0x7f197ea8fab0 - thunk::F.Invoke<A, R>::invoke::h16144672682574185653
  24:     0x7f197e3c4050 - sys::thread::thread_start::h76415ad3898ce7eaaOE
  25:     0x7f19783c7250 - start_thread
  26:     0x7f197dfb8219 - clone
  27:                0x0 - <unknown>

[codyps]

I've seen this too with:

Reproducer:

fn main() {
        let _ : Box<Fn([u8])> = Box::new(|ref _a| {});
}

Version:

rustc 1.0.0-nightly (91bdf23f5 2015-03-09) (built 2015-03-09)

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
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'unsized_part_of_type failed even though ty is unsized', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/librustc_trans/trans/common.rs:168

stack backtrace:
   1:     0x7f79f57642f2 - sys::backtrace::write::hd861c9cad5664affQBA
   2:     0x7f79f578a342 - panicking::on_panic::h2d36a117ae395cb9jHJ
   3:     0x7f79f56d0a89 - rt::unwind::begin_unwind_inner::h020c424433824dc2mnJ
   4:     0x7f79f4decf8c - rt::unwind::begin_unwind::h13525811864842182597
   5:     0x7f79f4ea8a1b - trans::common::unsized_part_of_type::h58de00457dffddfcVxk
   6:     0x7f79f4e4f5b2 - trans::type_of::in_memory_type_of::hf3dc8a7490292449DHo
   7:     0x7f79f4ee8543 - trans::base::trans_closure::h70b835bf44b08f62ent
   8:     0x7f79f4e9fe2e - trans::closure::trans_closure_expr::he9af68f514bf9e21Gnx
   9:     0x7f79f4ecde63 - trans::consts::const_expr_unadjusted::hf36c0cdf480a0885ZTn
  10:     0x7f79f4ed1667 - trans::consts::const_expr::h29a9ed2c5e375d82tHn
  11:     0x7f79f4e6bcde - trans::consts::get_const_expr_as_global::hcd5ecd875acacf4bEEn
  12:     0x7f79f4e2ebfc - trans::expr::trans::h66ceb310b9edf1f9bwh
  13:     0x7f79f4e6086b - trans::callee::trans_args::hf2cfa069a4970bdbG3g
  14:     0x7f79f4e6624c - trans::callee::trans_call_inner::h17056753389190948462
  15:     0x7f79f4e6f077 - trans::expr::trans_rvalue_dps_unadjusted::hbd2cd1fd54de27cayCi
  16:     0x7f79f4e6d1bb - trans::expr::trans_unadjusted::h98b3a24d34abc9f436h
  17:     0x7f79f4e2f0e0 - trans::expr::trans::h66ceb310b9edf1f9bwh
  18:     0x7f79f4e2d625 - trans::expr::trans_to_lvalue::h8c97fd7e77062732c6h
  19:     0x7f79f4e2d18d - trans::base::init_local::h6b5a17c439dc15bfGBs
  20:     0x7f79f4e2e662 - trans::controlflow::trans_block::h47e6e8902755cf9cv7d
  21:     0x7f79f4ee9ed0 - trans::base::trans_closure::h70b835bf44b08f62ent
  22:     0x7f79f4e1df4b - trans::base::trans_fn::h88672d255f7695867xt
  23:     0x7f79f4e19ef6 - trans::base::trans_item::h1cf2dcffa3cf86bfZVt
  24:     0x7f79f4ef067c - trans::base::trans_crate::h88960ef764a955bcaSu
  25:     0x7f79f5d88f92 - driver::phase_4_translate_to_llvm::h5d3ca9bd44c7f33agOa
  26:     0x7f79f5d648ea - driver::compile_input::h124aae68147ae8b8Nba
  27:     0x7f79f5e2915d - run_compiler::hffd5283ae5d6d3abG6b
  28:     0x7f79f5e26ecc - thunk::F.Invoke<A, R>::invoke::h16438916220137010031
  29:     0x7f79f5e25b20 - rt::unwind::try::try_fn::h17325604874211535233
  30:     0x7f79f57f6118 - rust_try_inner
  31:     0x7f79f57f6105 - rust_try
  32:     0x7f79f5e262ab - thunk::F.Invoke<A, R>::invoke::h5807416775295653773
  33:     0x7f79f5777b45 - sys::thread::thread_start::h2188587ec04914c6t8E
  34:     0x7f79ef7e4373 - start_thread
  35:     0x7f79f535927c - __clone
  36:                0x0 - <unknown>

[Stebalien]

fn main() {
        let _ : Box<Fn([u8])> = Box::new(|ref _a| {});
}

No longer reproduces but the other tests do.

[arielb1]

cc #25388

[comex]

Is this the same as or related to #24957?

[AndiDog]

use std::path::Path;
use std::path::PathBuf;

pub enum Source
{
    File(Path), // compiler error :(
    // File(PathBuf), // works :)
}

pub fn source_to_dbtype(src: &Source) -> u8
{
    match src
    {
        &Source::File(..) => 1,
    }
}

leads to thread 'rustc' panicked at 'Unexpected type returned from struct_tail: Source for ty=Source', src/librustc_trans/trans/type_of.rs:385. As mentioned inline, using the correct type works (PathBuf).

I'm using the Ubuntu PPA "rust-nightly", version 201509240405f0666b4vivid.