ICE with add lang-item with generic param

[jruderman]

Fuzzing found this by modifying src/test/ui/associated-types/associated-types-ICE-when-projecting-out-of-err.rs.

The key modification is adding a generic parameter to the add method of the add lang-item.

NB: It still ICEs even without no_core, after noting "duplicate lang item".

Code

#![crate_type = "lib"]
#![feature(lang_items)]
#![feature(no_core)]
#![no_core]

#[lang="sized"]
pub trait Sized {
    // Empty.
}

#[lang = "add"]
trait Add<RHS=Self> {
    type Output;

    fn add<Y>(self, _: RHS) -> Self::Output;
}

#[allow(unreachable_code)]
fn ice(a: usize) {
    let r = loop {};
    r = r + a;
}

Error output

thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `1`,
 right: `0`', compiler/rustc_hir_typeck/src/method/mod.rs:446:9

The assertion is in construct_obligation_for_trait:

assert_eq!(generics.params.len(), 0);

Backtrace

stack backtrace:
   0:        0x101e6e7a2 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hde9930b8710af522
   1:        0x101ec65ea - core::fmt::write::hd25ec0bfc1849a2f
   2:        0x101e6087c - std::io::Write::write_fmt::hca36d7396c5dc18b
   3:        0x101e6e56a - std::sys_common::backtrace::print::hc155979e9e33e658
   4:        0x101e71946 - std::panicking::default_hook::{{closure}}::h03db778ae686f347
   5:        0x101e71697 - std::panicking::default_hook::h0d9e8bcb55be071f
   6:        0x10cf3b7dd - rustc_driver[77a613ab63d15aac]::DEFAULT_HOOK::{closure#0}::{closure#0}
   7:        0x101e72145 - std::panicking::rust_panic_with_hook::h758520931cfdfde5
   8:        0x101e71ed3 - std::panicking::begin_panic_handler::{{closure}}::hbd614a4fa39cd06c
   9:        0x101e6ec38 - std::sys_common::backtrace::__rust_end_short_backtrace::h79fc17c09554573a
  10:        0x101e71b9d - _rust_begin_unwind
  11:        0x101ef30b3 - core::panicking::panic_fmt::he2b6cedac2bde968
  12:        0x101ec329a - core::panicking::assert_failed_inner::ha6a1dd7406f04693
  13:        0x111c3096e - core[cfd2f0869b685cd6]::panicking::assert_failed::<usize, usize>
  14:        0x10f80350f - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::construct_obligation_for_trait
  15:        0x10f808c7a - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::lookup_op_method
  16:        0x10f804633 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_overloaded_binop
  17:        0x10f8042f3 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_binop
  18:        0x10f81e133 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_expr_kind
  19:        0x10f7c69c0 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  20:        0x10f81f4ab - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_expr_kind
  21:        0x10f7c69c0 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  22:        0x10f7dc435 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_stmt
  23:        0x10f7dcb5f - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_block_with_expected
  24:        0x10f81d188 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_expr_kind
  25:        0x10f7c69c0 - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  26:        0x10f7c79fa - <rustc_hir_typeck[716c980e434cc4b7]::fn_ctxt::FnCtxt>::check_return_expr
  27:        0x10f8d08cf - rustc_hir_typeck[716c980e434cc4b7]::check::check_fn
  28:        0x10f8fc894 - rustc_hir_typeck[716c980e434cc4b7]::typeck
  29:        0x1107a95a9 - rustc_query_system[69ea88315c8057f7]::query::plumbing::try_execute_query::<rustc_query_impl[44c1f9c305efea75]::plumbing::QueryCtxt, rustc_query_system[69ea88315c8057f7]::query::caches::DefaultCache<rustc_span[48482e0f8f724117]::def_id::LocalDefId, &rustc_middle[b315a0ebd84f913d]::ty::context::TypeckResults>>
  30:        0x1108a5b6c - rustc_query_system[69ea88315c8057f7]::query::plumbing::get_query::<rustc_query_impl[44c1f9c305efea75]::queries::typeck, rustc_query_impl[44c1f9c305efea75]::plumbing::QueryCtxt>
  31:        0x10f92592b - rustc_data_structures[d9a04b93d3448b55]::sync::par_for_each_in::<&[rustc_span[48482e0f8f724117]::def_id::LocalDefId], <rustc_middle[b315a0ebd84f913d]::hir::map::Map>::par_body_owners<rustc_hir_typeck[716c980e434cc4b7]::typeck_item_bodies::{closure#0}>::{closure#0}>
  32:        0x10f8f9ded - rustc_hir_typeck[716c980e434cc4b7]::typeck_item_bodies
  33:        0x110839d99 - rustc_query_system[69ea88315c8057f7]::query::plumbing::try_execute_query::<rustc_query_impl[44c1f9c305efea75]::plumbing::QueryCtxt, rustc_query_system[69ea88315c8057f7]::query::caches::DefaultCache<(), ()>>
  34:        0x11089a319 - rustc_query_system[69ea88315c8057f7]::query::plumbing::get_query::<rustc_query_impl[44c1f9c305efea75]::queries::typeck_item_bodies, rustc_query_impl[44c1f9c305efea75]::plumbing::QueryCtxt>
  35:        0x10fa29284 - <rustc_session[ae5bb785c2cd4c22]::session::Session>::time::<(), rustc_hir_analysis[ad14f4770cb1b48d]::check_crate::{closure#7}>
  36:        0x10f9d4caf - rustc_hir_analysis[ad14f4770cb1b48d]::check_crate
  37:        0x10d08284a - rustc_interface[a0d981abc9377f30]::passes::analysis
  38:        0x11082bb5c - rustc_query_system[69ea88315c8057f7]::query::plumbing::try_execute_query::<rustc_query_impl[44c1f9c305efea75]::plumbing::QueryCtxt, rustc_query_system[69ea88315c8057f7]::query::caches::DefaultCache<(), core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>>
  39:        0x1108a5f19 - rustc_query_system[69ea88315c8057f7]::query::plumbing::get_query::<rustc_query_impl[44c1f9c305efea75]::queries::analysis, rustc_query_impl[44c1f9c305efea75]::plumbing::QueryCtxt>
  40:        0x10cf577e6 - <rustc_interface[a0d981abc9377f30]::passes::QueryContext>::enter::<rustc_driver[77a613ab63d15aac]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>
  41:        0x10cf9bf5d - rustc_span[48482e0f8f724117]::with_source_map::<core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>, rustc_interface[a0d981abc9377f30]::interface::run_compiler<core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>, rustc_driver[77a613ab63d15aac]::run_compiler::{closure#1}>::{closure#0}::{closure#1}>
  42:        0x10cf8ba7c - <scoped_tls[46b3c18c0a12f0bc]::ScopedKey<rustc_span[48482e0f8f724117]::SessionGlobals>>::set::<rustc_interface[a0d981abc9377f30]::interface::run_compiler<core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>, rustc_driver[77a613ab63d15aac]::run_compiler::{closure#1}>::{closure#0}, core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>
  43:        0x10cf5b3ca - std[11391ffec397fd56]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[a0d981abc9377f30]::util::run_in_thread_pool_with_globals<rustc_interface[a0d981abc9377f30]::interface::run_compiler<core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>, rustc_driver[77a613ab63d15aac]::run_compiler::{closure#1}>::{closure#0}, core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>
  44:        0x10cf414cb - <<std[11391ffec397fd56]::thread::Builder>::spawn_unchecked_<rustc_interface[a0d981abc9377f30]::util::run_in_thread_pool_with_globals<rustc_interface[a0d981abc9377f30]::interface::run_compiler<core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>, rustc_driver[77a613ab63d15aac]::run_compiler::{closure#1}>::{closure#0}, core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[cfd2f0869b685cd6]::result::Result<(), rustc_errors[ec87cacb996b1da1]::ErrorGuaranteed>>::{closure#1} as core[cfd2f0869b685cd6]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  45:        0x101e7b1f7 - std::sys::unix::thread::Thread::new::thread_start::ha121f0b94f5d418a
  46:     0x7ff814d514e1 - __pthread_start

Version

rustc 1.67.0-nightly (7eef946fc 2022-11-06)
binary: rustc
commit-hash: 7eef946fc0e0eff40e588eab77b09b287accbec3
commit-date: 2022-11-06
host: x86_64-apple-darwin
release: 1.67.0-nightly
LLVM version: 15.0.4

[Noratrieb]

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