Calling a function declared in the Sized trait from a pub function results in an ICE

[Aiden2207]

The following bare bones no_core program results in an ICE.

#![no_std]
#![no_core]
#![feature(lang_items)]
#![feature(no_core)]


#[lang = "sized"]
pub trait Sized {
  fn foo(){}
}

pub fn bar() {
    u16::foo();
}

Playground

Error output

thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', compiler/rustc_monomorphize/src/collector.rs:894:93
stack backtrace:
   0: rust_begin_unwind
             at /rustc/e269e6bf47f40c9046cd44ab787881d700099252/library/std/src/panicking.rs:495:5
   1: core::panicking::panic_fmt
             at /rustc/e269e6bf47f40c9046cd44ab787881d700099252/library/core/src/panicking.rs:107:14
   2: core::panicking::panic
             at /rustc/e269e6bf47f40c9046cd44ab787881d700099252/library/core/src/panicking.rs:50:5
   3: rustc_monomorphize::collector::collect_neighbours
   4: rustc_monomorphize::collector::collect_items_rec
   5: <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}>
   6: rustc_monomorphize::collector::collect_crate_mono_items
   7: rustc_monomorphize::partitioning::collect_and_partition_mono_items
   8: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), (&std::collections::hash::set::HashSet<rustc_span::def_id::DefId, core::hash::BuildHasherDefault<rustc_hash::FxHasher>>, &[rustc_middle::mir::mono::CodegenUnit])>>
   9: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::collect_and_partition_mono_items, rustc_query_impl::plumbing::QueryCtxt>
  10: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::collect_and_partition_mono_items
  11: rustc_codegen_ssa::back::symbol_export::exported_symbols_provider_local
  12: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::CrateNum, &[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportLevel)]>>
  13: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::exported_symbols, rustc_query_impl::plumbing::QueryCtxt>
  14: <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root
  15: rustc_metadata::rmeta::encoder::encode_metadata_impl
  16: rustc_data_structures::sync::join::<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, rustc_metadata::rmeta::encoder::EncodedMetadata, ()>
  17: rustc_metadata::rmeta::encoder::encode_metadata
  18: <rustc_interface::passes::QueryContext>::enter::<<rustc_interface::queries::Queries>::ongoing_codegen::{closure#0}::{closure#0}, core::result::Result<alloc::boxed::Box<dyn core::any::Any>, rustc_errors::ErrorReported>>
  19: <rustc_interface::queries::Queries>::ongoing_codegen
  20: <rustc_interface::interface::Compiler>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_errors::ErrorReported>>
  21: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#0}>
  22: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose 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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.58.0-nightly (e269e6bf4 2021-10-26) running on x86_64-unknown-linux-gnu

note: compiler flags: -C embed-bitcode=no -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 [collect_and_partition_mono_items] collect_and_partition_mono_items
#1 [exported_symbols] exported_symbols
end of query stack
error: could not compile `playground` 

Interestingly, if you remove the pub from bar it compiles fine. The most sensible thing to do is probably disallow adding methods to the Sized lang item.

[asquared31415]

would be covered by #9307, but this is an interesting and new example!

[asquared31415]

@rustbot label +A-lang-item

[Noratrieb]

wontfix