Rust internal compiler error

[aleksanb]

I managed to crash the nightly compiler!

I tried this code:

fn main() {
    println!("Hello, world!");
}

trait functor<A, B, F: Fn(A) -> B> {
    type Output;

    fn map(&mut self, F) -> Self::Output;
}

impl<A, B, F: Fn(A) -> B> functor<A, B, F> for Option<A> {
    type Output = Option<B>;

    fn map(&mut self, f: F) -> B { 
        f(*self)
    }   
}

I expected the code to (perhaps) compile successfully.
Instead, this happened:

aleksanb@Capitalism-2:~/Projects/rust/functor$ RUST_BACKTRACE=1 cargo run --verbose
   Compiling functor v0.1.0 (file:///home/aleksanb/Projects/rust/functor)
     Running `rustc src/main.rs --crate-name functor --crate-type bin -g -C metadata=d523fcdd903acc69 --out-dir /home/aleksanb/Projects/rust/functor/target/debug --emit=dep-info,link -L dependency=/home/aleksanb/Projects/rust/functor/target/debug/deps`
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 'called `Option::unwrap()` on a `None` value', ../src/libcore/option.rs:326
stack backtrace:
   1:     0x7fa479f95c63 - std::sys::backtrace::tracing::imp::write::h482d45d91246faa2
   2:     0x7fa479fa7d6c - std::panicking::default_hook::_{{closure}}::h89158f66286b674e
   3:     0x7fa479fa5fe7 - std::panicking::default_hook::h9e30d428ee3b0c43
   4:     0x7fa479fa67f8 - std::panicking::rust_panic_with_hook::h2224f33fb7bf2f4c
   5:     0x7fa479fa6692 - std::panicking::begin_panic::hcb11a4dc6d779ae5
   6:     0x7fa479fa65c0 - std::panicking::begin_panic_fmt::h310416c62f3935b3
   7:     0x7fa479fa6541 - rust_begin_unwind
   8:     0x7fa47a011cff - core::panicking::panic_fmt::hc5789f4e80194729
   9:     0x7fa47a011c2b - core::panicking::panic::h1953378f4b37b561
  10:     0x7fa478680ecc - rustc_typeck::check::compare_method::compare_impl_method::_{{closure}}::h08bef90d287aed42
  11:     0x7fa4785dcc99 - rustc_typeck::check::compare_method::compare_impl_method::he3538453c2efe177
  12:     0x7fa4785f1c22 - rustc_typeck::check::check_impl_items_against_trait::hb105ca8bb42a0b3d
  13:     0x7fa4785ef1a2 - rustc_typeck::check::check_item_type::hba3733559d49be1e
  14:     0x7fa4785e79eb - _<rustc_typeck..check..CheckItemTypesVisitor<'a, 'tcx> as rustc..hir..intravisit..Visitor<'tcx>>::visit_item::h369cacffbaa18923
  15:     0x7fa4785e98eb - rustc_typeck::check::check_item_types::h81e44a5d40f450fd
  16:     0x7fa47866128d - rustc_typeck::check_crate::h8ec8b2f490f5dc28
  17:     0x7fa47a391a03 - rustc_driver::driver::phase_3_run_analysis_passes::_{{closure}}::h45e03cee16dcf298
  18:     0x7fa47a35db21 - rustc_driver::driver::phase_3_run_analysis_passes::hc0de40cea97d81a1
  19:     0x7fa47a34a146 - rustc_driver::driver::compile_input::hd9ecc57abd3cba85
  20:     0x7fa47a37d656 - rustc_driver::run_compiler::h184264500271cc39
  21:     0x7fa47a2b88c2 - std::panicking::try::do_call::h17a7a17ad7240c5c
  22:     0x7fa479fb60d6 - __rust_maybe_catch_panic
  23:     0x7fa47a2d22aa - _<F as alloc..boxed..FnBox<A>>::call_box::h93f9128277b2964a
  24:     0x7fa479fa43b2 - std::sys::thread::Thread::new::thread_start::he0bf102845911132
  25:     0x7fa4722816f9 - start_thread
  26:     0x7fa479be4b5c - clone
  27:                0x0 - <unknown>

error: Could not compile `functor`.

Caused by:
  Process didn't exit successfully: `rustc src/main.rs --crate-name functor --crate-type bin -g -C metadata=d523fcdd903acc69 --out-dir /home/aleksanb/Projects/rust/functor/target/debug --emit=dep-info,link -L dependency=/home/aleksanb/Projects/rust/functor/target/debug/deps` (exit code: 101)

I'm not quite sure what to do from here 💃

Meta

rustc 1.13.0-nightly (3c5a0fa 2016-08-22)
binary: rustc
commit-hash: 3c5a0fa
commit-date: 2016-08-22
host: x86_64-unknown-linux-gnu
release: 1.13.0-nightly

[TimNN]

Duplicate of #35869,

the actual error is

error: method `map` has an incompatible type for trait:
 expected enum `std::option::Option`,
    found type parameter [--explain E0053]
  --> <anon>:14:5
   |>
14 |>     fn map(&mut self, f: F) -> B {
   |>     ^

error: aborting due to previous error

(You'll get that on stable, beta and any nightlies before nightly-2016-08-18.