internal compiler error: librustc_mir/monomorphize/collector.rs:765: Cannot create local mono-item for DefId(11/0:1282 ~ serenity[fa52]::gateway[0]::shard_manager[0]::start_shard[0])

[FelixMcFelix]

Attempting to compile the subproject examples/dev_shard_manager/ with cargo run in this commit/library version causes the compiler to panic with the following output on stable, beta and nightly.

I expect the code in examples/dev_shard_manager/main.rs is incorrect in some way, but regardless the compiler should not panic.

EDIT: Specifically, the lines https://github.com/FelixMcFelix/serenity/blob/ee8bfa1fa3a9c9a5f4a1c49283921e9cd7e4953a/examples/dev_shard_manager/src/main.rs#L47--48 are at fault. cargo check works, and reports that the program should compile.

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rustc --version --verbose (for nightly):
rustc 1.28.0-nightly (f28c7aef7 2018-06-19) binary: rustc commit-hash: f28c7aef7fbff1909c2d0257186cd7a5f0c6aa4b commit-date: 2018-06-19 host: x86_64-unknown-linux-gnu release: 1.28.0-nightly LLVM version: 6.0

Backtrace:

error: internal compiler error: librustc_mir/monomorphize/collector.rs:765: Cannot create local mono-item for DefId(11/0:1282 ~ serenity[fa52]::gateway[0]::shard_manager[0]::start_shard[0])

thread 'main' panicked at 'Box<Any>', librustc_errors/lib.rs:554:9
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::print
             at libstd/sys_common/backtrace.rs:71
             at libstd/sys_common/backtrace.rs:59
   2: std::panicking::default_hook::{{closure}}
             at libstd/panicking.rs:211
   3: std::panicking::default_hook
             at libstd/panicking.rs:227
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at libstd/panicking.rs:515
   6: std::panicking::begin_panic
   7: rustc_errors::Handler::bug
   8: rustc::session::opt_span_bug_fmt::{{closure}}
   9: rustc::ty::context::tls::with_opt::{{closure}}
  10: rustc::ty::context::tls::with_context_opt
  11: rustc::ty::context::tls::with_opt
  12: rustc::session::opt_span_bug_fmt
  13: rustc::session::bug_fmt
  14: rustc_mir::monomorphize::collector::should_monomorphize_locally
  15: rustc_mir::monomorphize::collector::visit_instance_use
  16: <rustc_mir::monomorphize::collector::MirNeighborCollector<'a, 'tcx> as rustc::mir::visit::Visitor<'tcx>>::visit_terminator_kind
  17: rustc_mir::monomorphize::collector::collect_items_rec
  18: rustc_mir::monomorphize::collector::collect_items_rec
  19: rustc_mir::monomorphize::collector::collect_items_rec
  20: rustc_mir::monomorphize::collector::collect_items_rec
  21: rustc_mir::monomorphize::collector::collect_items_rec
  22: rustc_mir::monomorphize::collector::collect_items_rec
  23: rustc_mir::monomorphize::collector::collect_items_rec
  24: rustc_mir::monomorphize::collector::collect_items_rec
  25: rustc_mir::monomorphize::collector::collect_items_rec
  26: rustc_mir::monomorphize::collector::collect_items_rec
  27: rustc_mir::monomorphize::collector::collect_items_rec
  28: rustc_mir::monomorphize::collector::collect_items_rec
  29: rustc_mir::monomorphize::collector::collect_items_rec
  30: rustc_mir::monomorphize::collector::collect_items_rec
  31: rustc_mir::monomorphize::collector::collect_items_rec
  32: rustc_mir::monomorphize::collector::collect_crate_mono_items::{{closure}}
  33: rustc::util::common::time
  34: rustc_mir::monomorphize::collector::collect_crate_mono_items
  35: rustc::util::common::time
  36: rustc_codegen_llvm::base::collect_and_partition_mono_items
  37: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::collect_and_partition_mono_items<'tcx>>::compute
  38: rustc::ty::context::tls::with_context
  39: rustc::dep_graph::graph::DepGraph::with_task_impl
  40: rustc::ty::context::tls::with_related_context
  41: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
  42: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  43: rustc_codegen_llvm::base::codegen_crate
  44: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
  45: rustc::util::common::time
  46: rustc_driver::driver::phase_4_codegen
  47: rustc_driver::driver::compile_input::{{closure}}
  48: rustc::ty::context::tls::enter_context
  49: <std::thread::local::LocalKey<T>>::with
  50: rustc::ty::context::TyCtxt::create_and_enter
  51: rustc_driver::driver::compile_input
  52: rustc_driver::run_compiler_with_pool
  53: <scoped_tls::ScopedKey<T>>::set
  54: syntax::with_globals
  55: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  56: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:105
  57: rustc_driver::run
  58: rustc_driver::main
  59: std::rt::lang_start::{{closure}}
  60: std::panicking::try::do_call
             at libstd/rt.rs:59
             at libstd/panicking.rs:310
  61: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:105
  62: std::rt::lang_start_internal
             at libstd/panicking.rs:289
             at libstd/panic.rs:392
             at libstd/rt.rs:58
  63: main
  64: __libc_start_main
  65: <unknown>
query stack during panic:
#0 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
error: aborting due to previous error

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 1.28.0-nightly (f28c7aef7 2018-06-19) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

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

error: Could not compile `dev_shard_manager`.

[FelixMcFelix]

Seems to be a duplicate of #50865. Closing.