ICE: `expected item, found unknown node`, caused by reexport.

[rodrimati1992]

Attempting to compile this code:

extern crate self as playground;

pub struct Hello;

pub use crate::playground::Hello as world;

Playground link: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=9ee5284237231c2287488a22ec49230a

Causes this ICE in nightly 2019-12-29 ,and stable with a slightly different stack trace.

error: internal compiler error: src/librustc/hir/map/mod.rs:882: expected item, found unknown node (hir_id=HirId { owner: DefIndex(0), local_id: 0 })

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:889:9
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:77
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1057
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1426
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:195
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:215
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:476
  12: std::panicking::begin_panic
  13: rustc_errors::HandlerInner::bug
  14: rustc_errors::Handler::bug
  15: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  16: rustc::ty::context::tls::with_opt::{{closure}}
  17: rustc::ty::context::tls::with_opt
  18: rustc::util::bug::opt_span_bug_fmt
  19: rustc::util::bug::bug_fmt
  20: rustc::hir::map::Map::expect_item
  21: <rustc_privacy::EmbargoVisitor as rustc::hir::intravisit::Visitor>::visit_item
  22: <rustc_privacy::EmbargoVisitor as rustc::hir::intravisit::Visitor>::visit_mod
  23: rustc_privacy::privacy_access_levels
  24: rustc::ty::query::__query_compute::privacy_access_levels
  25: rustc::dep_graph::graph::DepGraph::with_task_impl
  26: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  27: rustc::util::common::time
  28: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  29: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:79
  30: rustc_interface::passes::analysis::{{closure}}
  31: rustc::util::common::time
  32: rustc_interface::passes::analysis
  33: rustc::ty::query::__query_compute::analysis
  34: rustc::dep_graph::graph::DepGraph::with_task_impl
  35: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  36: rustc::ty::context::tls::enter_global
  37: rustc_interface::interface::run_compiler_in_existing_thread_pool
  38: scoped_tls::ScopedKey<T>::set
  39: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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: rustc 1.42.0-nightly (da3629b05 2019-12-29) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [privacy_access_levels] privacy access levels
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

error: could not compile `playground`.

[DutchGhost]

reduced to 2 lines:

pub extern crate self as name;
pub use name::name as bug;

also, when the pub is removed from the use line, OR both pub's are removed, it compiles fine.

[JohnTitor]

@Centril yeah, I prepared the fix but @varkor has already submitted another fix so assignment is unnecessary?