ICE: Type parameter out of range when substituting in region 'a (space=FnSpace, index=0)

[vhbit]

Unfortunately I've failed to understand what exactly causes it as reported 'a core::NativeTransaction is used just in a couple of places and looks completely innocent.

I believe it started after #18121 landed.

Here is a backtrace:

/Users/vhbit/projects/lmdb-rs/src/lib.rs:1:1: 1:1 error: internal compiler error: Type parameter out of range when substituting in region 'a (root type='acore::NativeTransaction) (space=FnSpace, index=0)
/Users/vhbit/projects/lmdb-rs/src/lib.rs:1 #![crate_name = "lmdb"]
                                           ^
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 'Box<Any>', /Users/vhbit/projects/auto-rust/src/libsyntax/diagnostic.rs:116

stack backtrace:
   1:        0x10f254299 - rt::backtrace::imp::write::h6f68f12355c8d0e2mlq
   2:        0x10f257577 - failure::on_fail::he53cd18c9c48fe7cVBq
   3:        0x10f4ba675 - unwind::begin_unwind_inner::h532adb3b47d70b2aDud
   4:        0x10e9ab687 - unwind::begin_unwind::h13945917757193214155
   5:        0x10e9ab620 - unwind::begin_unwind::h13945917757193214155
   6:        0x10c2d2c13 - middle::subst::SubstFolder<'a, 'tcx>.TypeFolder<'tcx>::fold_region::hf439d6ca506a1235J8V
   7:        0x10c20ab96 - middle::subst::SubstFolder<'a, 'tcx>.TypeFolder<'tcx>::fold_ty::h6b224cbf27a1f8b0PaW
   8:        0x10c4aab18 - middle::typeck::check::method::LookupContext<'a, 'tcx>::xform_self_ty::h8b8bf7076e90ad97bdU
   9:        0x10c4a96bd - middle::typeck::check::method::LookupContext<'a, 'tcx>::push_inherent_impl_candidates_for_type::h149b1a403c6e9c8d4US
  10:        0x10c4a9103 - middle::typeck::check::method::LookupContext<'a, 'tcx>::push_inherent_candidates::closure.130669
  11:        0x10c4a8af5 - middle::typeck::check::autoderef::h1138707213401754793
  12:        0x10c49f192 - middle::typeck::check::method::lookup::h656fa83e72c76904vGR
  13:        0x10c4fdebb - middle::typeck::check::check_expr_with_unifier::ha848438f23402a7dCsY
  14:        0x10c4c72e0 - middle::typeck::check::check_block_with_expected::hdc28d4c9d3fea42a0A0
  15:        0x10c4c2b44 - middle::typeck::check::check_fn::h84feddd5d2edf884LfV
  16:        0x10c4c200b - middle::typeck::check::check_bare_fn::he86fef689e6d9102T4U
  17:        0x10c4c9a10 - middle::typeck::check::check_method_body::ha706363df14218ddEzV
  18:        0x10c4bee98 - middle::typeck::check::check_item::hf51938155885a1b8UoV
  19:        0x10c4c02e3 - visit::walk_item::h11639469492027250940
  20:        0x10c4c1e6a - middle::typeck::check::check_item_types::hbb9da7acb2b363e033U
  21:        0x10bf87d56 - util::common::time::h17357078438074708411
  22:        0x10c79062e - middle::typeck::check_crate::h0ccf9d9f552899b3xLn
  23:        0x10c7fbcff - driver::driver::phase_3_run_analysis_passes::h5c7782ef6e7c62e6fpA
  24:        0x10c7f6cae - driver::driver::compile_input::h0f5f8287137a89d705z
  25:        0x10c87b23f - driver::run_compiler::hef0d18d631a92f7abTD
  26:        0x10c8793c6 - driver::run::closure.144873
  27:        0x10bfa141b - task::TaskBuilder<S>::try_future::closure.103271
  28:        0x10bfa1303 - task::TaskBuilder<S>::spawn_internal::closure.103242
  29:        0x10bf1e8fd - task::NativeSpawner.Spawner::spawn::closure.8527
  30:        0x10f524b3c - rust_try_inner
  31:        0x10f524b26 - rust_try
  32:        0x10f4b7ce7 - unwind::try::hf6abc66f61cc4b23ljd
  33:        0x10f4b7b6c - task::Task::run::h4e050f8fa3cba51ewzc
  34:        0x10bf1e722 - task::NativeSpawner.Spawner::spawn::closure.8466
  35:        0x10f4b952a - thread::thread_start::h8fed07902f91253fHTc
  36:     0x7fff9406b899 - _pthread_body
  37:     0x7fff9406b72a - _pthread_struct_init

[vhbit]

cc @nikomatsakis

[vhbit]

After commenting out everything what somehow uses NativeTransaction I've got Type parameter out of range when substituting in region 'a (root type='aSelf) (space=FnSpace, index=0) and stopped here as there is too much to comment out if trying to remove all traits.

[pythonesque]

Having the same issue.

[vhbit]

Here is so far smallest piece of code which causes it:

#![allow(dead_code)]

struct Cursor<'a>;

trait CursorNavigator {
    fn init_cursor<'a, 'b:'a>(&'a self, cursor: &mut Cursor<'b>) -> bool;
}

struct SimpleNavigator;

impl CursorNavigator for SimpleNavigator {
    fn init_cursor<'a, 'b: 'a>(&'a self, _cursor: &mut Cursor<'b>) -> bool {
        false
    }
}

fn main() {
    let mut c = Cursor;
    let n = SimpleNavigator;
    n.init_cursor(&mut c); // <-------------------- fails on resolving this method call
}

[vhbit]

So it seems the only thing which crashes it is a notion that 'b outlives 'a, if 'b is declared to be independent it has a problem compiling it.

Unfortunately there is no workaround it my case as if I remove this obligation I get compile errors in other parts.

[vhbit]

@nikomatsakis is there anything else I can provide to help fixing it?

[nikomatsakis]

Sorry, catching up on github notifications and only just saw this.

[nikomatsakis]

The reduced test case certainly helps a lot.

[IvanUkhov]

Hello,

I get a similar error

<anon>:1:1: 1:1 error: internal compiler error: Type parameter out of range when substituting in region 'a (root type='aBar) (space=FnSpace, index=0)
<anon>:1 extern crate test;
         ^
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
task 'rustc' panicked at 'Box<Any>', /build/rust-git/src/rust/src/libsyntax/diagnostic.rs:116

with the following code:

extern crate test;

trait Foo<'a> {
    fn foo(bar: &'a Bar) -> Self;
}

struct Bar;

struct Baz<'a> {
    bar: &'a Bar,
}

impl <'a> Foo<'a> for Baz<'a> {
    fn foo(bar: &'a Bar) -> Baz<'a> { Baz { bar: bar } }
}

impl Bar {
    fn foo<'a, T: Foo<'a>>(&'a self) -> T { Foo::foo(self) }
}

fn main() {
    let bar = Bar;
    let baz: Baz = bar.foo();
    test::black_box(baz.bar);
}

I hope it helps.

Regards,
Ivan

[vhbit]

@nikomatsakis any estimations on this issue? There is a tons of useful stuff in nightly and it is a bit pity to stay on 2 week old version just because one of deps produced ICE.

[nikomatsakis]

On Thu, Nov 06, 2014 at 01:04:45AM -0800, Valerii Hiora wrote:

@nikomatsakis any estimations on this issue? There is a tons of useful stuff in nightly and it is a bit pity to stay on 2 week old version just because one of deps produced ICE.

Hi, sorry, I've been busy pushing on new features, I plan to take some
time to investigate bugs (including this one).

[nikomatsakis]

OK, so, I figured out the fix. I will attach a patch on this pending PR: #18694

[vhbit]

ohh, it finally works! 👍