ICE using return_position_impl_trait_in_trait with default implementation

[matheus-consoli]

Code

playground

rustc panics on:

#![feature(return_position_impl_trait_in_trait)]
trait FilterOddsIteratorExt: Iterator<Item=usize> + Sized {
    fn filter_odds(self) -> impl Iterator<Item=usize> {
        self.filter(|i| i % 2 != 0)
    }
}

impl<T> FilterOddsIteratorExt for T where T: Iterator<Item = usize> {}


fn main() {
   _ = (0..10).filter_odds();
}

but not on:

trait FilterOddsIteratorExt: Iterator<Item=usize> + Sized {
    fn filter_odds(self) -> impl Iterator<Item = usize>;
}

impl<T> FilterOddsIteratorExt for T where T: Iterator<Item=usize> {
    fn filter_odds(self) -> impl Iterator<Item=usize> {
        self.filter(|i| i % 2 != 0)
    }
}

fn main() {
    _ = (0..10).filter_odds();
}

note that when not using the implementation, the compiler doesn't panic, but gives a mismatch types error (try commenting main)

Meta

rustc --version --verbose:

rustc 1.66.0-nightly (0ca356586 2022-10-06)
binary: rustc
commit-hash: 0ca356586fed56002b10920fd21ddf6fb12de797
commit-date: 2022-10-06
host: x86_64-unknown-linux-gnu
release: 1.66.0-nightly
LLVM version: 15.0.2

Backtrace

thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', compiler/rustc_hir_analysis/src/check/compare_method.rs:444:45
stack backtrace:
   0:     0x7f20db9a6450 - std::backtrace_rs::backtrace::libunwind::trace::hcf69096e68cbc96c
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   1:     0x7f20db9a6450 - std::backtrace_rs::backtrace::trace_unsynchronized::hc388a2eb8060d628
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f20db9a6450 - std::sys_common::backtrace::_print_fmt::h4c04c7375802901c
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7f20db9a6450 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h0437a8b14d91b76c
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7f20dba0121e - core::fmt::write::h3b1165d45b8cb3f7
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/core/src/fmt/mod.rs:1209:17
   5:     0x7f20db996fd5 - std::io::Write::write_fmt::h108967c06574ddc1
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/io/mod.rs:1679:15
   6:     0x7f20db9a91f3 - std::sys_common::backtrace::_print::haaa35276780afaf9
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7f20db9a91f3 - std::sys_common::backtrace::print::hbb2439e50cf7a680
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7f20db9a91f3 - std::panicking::default_hook::{{closure}}::h255e62e45345406e
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/panicking.rs:267:22
   9:     0x7f20db9a8eca - std::panicking::default_hook::h3a9c05016eae076b
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/panicking.rs:286:9
  10:     0x7f20de2cccd1 - <rustc_driver[f8d5eb37f9652177]::DEFAULT_HOOK::{closure#0}::{closure#0} as core[341adad06997dc31]::ops::function::FnOnce<(&core[341adad06997dc31]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  11:     0x7f20db9a9a2b - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h96fcb5350a0ce4d2
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/alloc/src/boxed.rs:1952:9
  12:     0x7f20db9a9a2b - std::panicking::rust_panic_with_hook::h1e087acdfd3a88b4
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/panicking.rs:673:13
  13:     0x7f20db9a9841 - std::panicking::begin_panic_handler::{{closure}}::h36afbf5dab2db68d
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/panicking.rs:558:13
  14:     0x7f20db9a68fc - std::sys_common::backtrace::__rust_end_short_backtrace::h8b338cf63632c037
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/sys_common/backtrace.rs:138:18
  15:     0x7f20db9a95a2 - rust_begin_unwind
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/panicking.rs:556:5
  16:     0x7f20db9fddf3 - core::panicking::panic_fmt::hbaf70a28dc8c539a
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/core/src/panicking.rs:142:14
  17:     0x7f20db9fdc3d - core::panicking::panic::h82a6ad6819b2af85
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/core/src/panicking.rs:48:5
  18:     0x7f20de4fc804 - rustc_hir_analysis[23b58cca7863dc36]::check::compare_method::collect_trait_impl_trait_tys
  19:     0x7f20deb61c44 - <rustc_middle[8fec32cc1d722bdc]::dep_graph::dep_node::DepKind as rustc_query_system[8eac85d8325cc65c]::dep_graph::DepKind>::with_deps::<<rustc_query_system[8eac85d8325cc65c]::dep_graph::graph::DepGraph<rustc_middle[8fec32cc1d722bdc]::dep_graph::dep_node::DepKind>>::with_task_impl<rustc_middle[8fec32cc1d722bdc]::ty::context::TyCtxt, rustc_span[97dc9a00dee87296]::def_id::DefId, core[341adad06997dc31]::result::Result<&std[ec613a431564c17a]::collections::hash::map::HashMap<rustc_span[97dc9a00dee87296]::def_id::DefId, rustc_middle[8fec32cc1d722bdc]::ty::Ty, core[341adad06997dc31]::hash::BuildHasherDefault<rustc_hash[ad1c7c67e0991a18]::FxHasher>>, rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>::{closure#0}, core[341adad06997dc31]::result::Result<&std[ec613a431564c17a]::collections::hash::map::HashMap<rustc_span[97dc9a00dee87296]::def_id::DefId, rustc_middle[8fec32cc1d722bdc]::ty::Ty, core[341adad06997dc31]::hash::BuildHasherDefault<rustc_hash[ad1c7c67e0991a18]::FxHasher>>, rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>
  20:     0x7f20decbf555 - <rustc_query_system[8eac85d8325cc65c]::dep_graph::graph::DepGraph<rustc_middle[8fec32cc1d722bdc]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[8fec32cc1d722bdc]::ty::context::TyCtxt, rustc_span[97dc9a00dee87296]::def_id::DefId, core[341adad06997dc31]::result::Result<&std[ec613a431564c17a]::collections::hash::map::HashMap<rustc_span[97dc9a00dee87296]::def_id::DefId, rustc_middle[8fec32cc1d722bdc]::ty::Ty, core[341adad06997dc31]::hash::BuildHasherDefault<rustc_hash[ad1c7c67e0991a18]::FxHasher>>, rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>
  21:     0x7f20debc8792 - rustc_query_system[8eac85d8325cc65c]::query::plumbing::try_execute_query::<rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt, rustc_query_system[8eac85d8325cc65c]::query::caches::DefaultCache<rustc_span[97dc9a00dee87296]::def_id::DefId, core[341adad06997dc31]::result::Result<&std[ec613a431564c17a]::collections::hash::map::HashMap<rustc_span[97dc9a00dee87296]::def_id::DefId, rustc_middle[8fec32cc1d722bdc]::ty::Ty, core[341adad06997dc31]::hash::BuildHasherDefault<rustc_hash[ad1c7c67e0991a18]::FxHasher>>, rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>>
  22:     0x7f20debf44ae - rustc_query_system[8eac85d8325cc65c]::query::plumbing::get_query::<rustc_query_impl[8927692615c9b81a]::queries::collect_trait_impl_trait_tys, rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt>
  23:     0x7f20df2de512 - <rustc_middle[8fec32cc1d722bdc]::ty::context::TyCtxt>::bound_trait_impl_trait_tys
  24:     0x7f20dcc9ef3c - rustc_trait_selection[88fd394d1feda7a5]::traits::project::opt_normalize_projection_type
  25:     0x7f20dcc92413 - <rustc_trait_selection[88fd394d1feda7a5]::traits::project::AssocTypeNormalizer as rustc_middle[8fec32cc1d722bdc]::ty::fold::TypeFolder>::fold_ty
  26:     0x7f20dd5d4aa3 - <&rustc_middle[8fec32cc1d722bdc]::ty::list::List<rustc_middle[8fec32cc1d722bdc]::ty::Ty> as rustc_middle[8fec32cc1d722bdc]::ty::fold::TypeFoldable>::try_fold_with::<rustc_trait_selection[88fd394d1feda7a5]::traits::project::AssocTypeNormalizer>
  27:     0x7f20dd5d495e - <(rustc_middle[8fec32cc1d722bdc]::ty::sty::FnSig, rustc_middle[8fec32cc1d722bdc]::ty::InstantiatedPredicates) as rustc_middle[8fec32cc1d722bdc]::ty::fold::TypeFoldable>::fold_with::<rustc_trait_selection[88fd394d1feda7a5]::traits::project::AssocTypeNormalizer>
  28:     0x7f20dd5d4003 - rustc_trait_selection[88fd394d1feda7a5]::traits::project::normalize::<(rustc_middle[8fec32cc1d722bdc]::ty::sty::FnSig, rustc_middle[8fec32cc1d722bdc]::ty::InstantiatedPredicates)>
  29:     0x7f20dce604f2 - <rustc_hir_analysis[23b58cca7863dc36]::check::method::confirm::ConfirmContext>::confirm
  30:     0x7f20dce264ec - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::lookup_method
  31:     0x7f20dce082c4 - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  32:     0x7f20dce46eef - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_decl
  33:     0x7f20dce4359e - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_block_with_expected
  34:     0x7f20dce0808b - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  35:     0x7f20dce434b9 - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_block_with_expected
  36:     0x7f20dce0808b - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  37:     0x7f20dd7f91a6 - <rustc_hir_analysis[23b58cca7863dc36]::check::fn_ctxt::FnCtxt>::check_return_expr
  38:     0x7f20dd7effa5 - rustc_hir_analysis[23b58cca7863dc36]::check::check::check_fn
  39:     0x7f20dd7e172b - <rustc_hir_analysis[23b58cca7863dc36]::check::inherited::InheritedBuilder>::enter::<rustc_hir_analysis[23b58cca7863dc36]::check::typeck_with_fallback<rustc_hir_analysis[23b58cca7863dc36]::check::typeck::{closure#0}>::{closure#1}, &rustc_middle[8fec32cc1d722bdc]::ty::context::TypeckResults>
  40:     0x7f20dd7df84f - rustc_hir_analysis[23b58cca7863dc36]::check::typeck
  41:     0x7f20dd8d4083 - <rustc_query_system[8eac85d8325cc65c]::dep_graph::graph::DepGraph<rustc_middle[8fec32cc1d722bdc]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[8fec32cc1d722bdc]::ty::context::TyCtxt, rustc_span[97dc9a00dee87296]::def_id::LocalDefId, &rustc_middle[8fec32cc1d722bdc]::ty::context::TypeckResults>
  42:     0x7f20dd8c2fb1 - rustc_query_system[8eac85d8325cc65c]::query::plumbing::try_execute_query::<rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt, rustc_query_system[8eac85d8325cc65c]::query::caches::DefaultCache<rustc_span[97dc9a00dee87296]::def_id::LocalDefId, &rustc_middle[8fec32cc1d722bdc]::ty::context::TypeckResults>>
  43:     0x7f20de1cad4e - <rustc_query_impl[8927692615c9b81a]::Queries as rustc_middle[8fec32cc1d722bdc]::ty::query::QueryEngine>::typeck
  44:     0x7f20ddffd6a7 - rustc_data_structures[af88eac711b540fa]::sync::par_for_each_in::<&[rustc_span[97dc9a00dee87296]::def_id::LocalDefId], <rustc_middle[8fec32cc1d722bdc]::hir::map::Map>::par_body_owners<rustc_hir_analysis[23b58cca7863dc36]::check::typeck_item_bodies::{closure#0}>::{closure#0}>
  45:     0x7f20ddffd463 - rustc_hir_analysis[23b58cca7863dc36]::check::typeck_item_bodies
  46:     0x7f20ddf00c49 - <rustc_query_system[8eac85d8325cc65c]::dep_graph::graph::DepGraph<rustc_middle[8fec32cc1d722bdc]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[8fec32cc1d722bdc]::ty::context::TyCtxt, (), ()>
  47:     0x7f20ddeffc28 - rustc_query_system[8eac85d8325cc65c]::query::plumbing::try_execute_query::<rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt, rustc_query_system[8eac85d8325cc65c]::query::caches::DefaultCache<(), ()>>
  48:     0x7f20ddeff637 - rustc_query_system[8eac85d8325cc65c]::query::plumbing::get_query::<rustc_query_impl[8927692615c9b81a]::queries::typeck_item_bodies, rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt>
  49:     0x7f20dd607fcf - <rustc_session[5f8ba50a91a4fb10]::session::Session>::time::<(), rustc_hir_analysis[23b58cca7863dc36]::check_crate::{closure#7}>
  50:     0x7f20dd607a2f - rustc_hir_analysis[23b58cca7863dc36]::check_crate
  51:     0x7f20dd6076d7 - rustc_interface[ef326ff72e9f2695]::passes::analysis
  52:     0x7f20de03e526 - <rustc_query_system[8eac85d8325cc65c]::dep_graph::graph::DepGraph<rustc_middle[8fec32cc1d722bdc]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[8fec32cc1d722bdc]::ty::context::TyCtxt, (), core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>
  53:     0x7f20de03dc06 - rustc_query_system[8eac85d8325cc65c]::query::plumbing::try_execute_query::<rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt, rustc_query_system[8eac85d8325cc65c]::query::caches::DefaultCache<(), core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>>
  54:     0x7f20de03d6e7 - rustc_query_system[8eac85d8325cc65c]::query::plumbing::get_query::<rustc_query_impl[8927692615c9b81a]::queries::analysis, rustc_query_impl[8927692615c9b81a]::plumbing::QueryCtxt>
  55:     0x7f20dcf9f484 - <rustc_interface[ef326ff72e9f2695]::passes::QueryContext>::enter::<rustc_driver[f8d5eb37f9652177]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>
  56:     0x7f20dcf9a019 - rustc_interface[ef326ff72e9f2695]::interface::create_compiler_and_run::<core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>, rustc_driver[f8d5eb37f9652177]::run_compiler::{closure#1}>
  57:     0x7f20dcf98922 - <scoped_tls[fa3665dae4c012d7]::ScopedKey<rustc_span[97dc9a00dee87296]::SessionGlobals>>::set::<rustc_interface[ef326ff72e9f2695]::interface::run_compiler<core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>, rustc_driver[f8d5eb37f9652177]::run_compiler::{closure#1}>::{closure#0}, core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>
  58:     0x7f20dcf9860f - std[ec613a431564c17a]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[ef326ff72e9f2695]::util::run_in_thread_pool_with_globals<rustc_interface[ef326ff72e9f2695]::interface::run_compiler<core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>, rustc_driver[f8d5eb37f9652177]::run_compiler::{closure#1}>::{closure#0}, core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>::{closure#0}, core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>
  59:     0x7f20de0e3530 - <<std[ec613a431564c17a]::thread::Builder>::spawn_unchecked_<rustc_interface[ef326ff72e9f2695]::util::run_in_thread_pool_with_globals<rustc_interface[ef326ff72e9f2695]::interface::run_compiler<core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>, rustc_driver[f8d5eb37f9652177]::run_compiler::{closure#1}>::{closure#0}, core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>::{closure#0}, core[341adad06997dc31]::result::Result<(), rustc_errors[827f592ed624eae5]::ErrorGuaranteed>>::{closure#1} as core[341adad06997dc31]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  60:     0x7f20db9b3503 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h716e33e5062fa80e
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/alloc/src/boxed.rs:1938:9
  61:     0x7f20db9b3503 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hda2b1d1f461e1c20
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/alloc/src/boxed.rs:1938:9
  62:     0x7f20db9b3503 - std::sys::unix::thread::Thread::new::thread_start::hcbf78f667b73439d
                               at /rustc/0ca356586fed56002b10920fd21ddf6fb12de797/library/std/src/sys/unix/thread.rs:108:17
  63:     0x7f20db72c8fd - <unknown>
  64:     0x7f20db7aea60 - <unknown>
  65:                0x0 - <unknown>

[compiler-errors]

This is a duplicate of #101665, so it's fixed by #101679. Thanks for reporting.