Type parameter `Self/#0` out of range when substituting

[nickgerace]

Using rustup on stable-aarch64-apple-darwin, I upgraded to Rust 1.65. Upon running cargo clean and fixing new clippy warnings (there were many, so it would be may to pin down a trigger, if applicable), I ran the following commands:

cargo clean # success
cargo build --all-targets # success
cargo clippy --no-deps --all-targets # fails with error below

The last command produces the following error:

error: internal compiler error: compiler/rustc_middle/src/ty/subst.rs:626:9: type parameter `Self/#0` (Self/0) out of range when substituting, substs=[]

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/897e37553bba8b42751c67658967889d11ecd120/compiler/rustc_errors/src/lib.rs:1462:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.65 (897e3755 2022-11-02)

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `redacted-crate-name`
warning: build failed, waiting for other jobs to finish...

Since the message recommended that I file a bug... here I am!

EDIT 1: the --all-targets flag appears to be the trigger.

EDIT 2: the issue appears to happen on both Linux (unknown-gnu) amd64 and macOS aarch64 systems using the corresponding their corresponding stable toolchains.

[zacharyhamm]

Seeing this as well. Here's a full backtrace

error: internal compiler error: compiler/rustc_middle/src/ty/subst.rs:626:9: type parameter `Self/#0` (Self/0) out of range when substituting, substs=[]

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/897e37553bba8b42751c67658967889d11ecd120/compiler/rustc_errors/src/lib.rs:1462:9
stack backtrace:
   0:     0x7f77f7241d40 - std::backtrace_rs::backtrace::libunwind::trace::h32eb3e08e874dd27
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f77f7241d40 - std::backtrace_rs::backtrace::trace_unsynchronized::haa3f451d27bc11a5
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f77f7241d40 - std::sys_common::backtrace::_print_fmt::h5b94a01bb4289bb5
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7f77f7241d40 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hb070b7fa7e3175df
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7f77f729cbfe - core::fmt::write::hd5207aebbb9a86e9
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/fmt/mod.rs:1202:17
   5:     0x7f77f7232935 - std::io::Write::write_fmt::h3bd699bbd129ab8a
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/io/mod.rs:1679:15
   6:     0x7f77f72449f3 - std::sys_common::backtrace::_print::h7a21be552fdf58da
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7f77f72449f3 - std::sys_common::backtrace::print::ha85c41fe4dd80b13
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7f77f72449f3 - std::panicking::default_hook::{{closure}}::h04cca40023d0eeca
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/panicking.rs:295:22
   9:     0x7f77f72446df - std::panicking::default_hook::haa3ca8c310ed5402
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/panicking.rs:314:9
  10:     0x560f7228c8af - clippy_driver[8edfe2ebdb33510b]::ICE_HOOK::{closure#0}::{closure#0}
  11:     0x7f77f724522d - std::panicking::rust_panic_with_hook::h7b190ce1a948faac
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/panicking.rs:702:17
  12:     0x7f77fa9f8e51 - std[71cb4861428b0c25]::panicking::begin_panic::<rustc_errors[f77a66b68db622d5]::ExplicitBug>::{closure#0}
  13:     0x7f77fa9f6966 - std[71cb4861428b0c25]::sys_common::backtrace::__rust_end_short_backtrace::<std[71cb4861428b0c25]::panicking::begin_panic<rustc_errors[f77a66b68db622d5]::ExplicitBug>::{closure#0}, !>
  14:     0x7f77faa50316 - std[71cb4861428b0c25]::panicking::begin_panic::<rustc_errors[f77a66b68db622d5]::ExplicitBug>
  15:     0x7f77fa9f35f6 - std[71cb4861428b0c25]::panic::panic_any::<rustc_errors[f77a66b68db622d5]::ExplicitBug>
  16:     0x7f77fa9f21dd - <rustc_errors[f77a66b68db622d5]::HandlerInner>::bug::<&alloc[188ed69dc0d14b4b]::string::String>
  17:     0x7f77fa9f1c10 - <rustc_errors[f77a66b68db622d5]::Handler>::bug::<&alloc[188ed69dc0d14b4b]::string::String>
  18:     0x7f77faaae7ed - rustc_middle[a9ca1c3f9fd197cd]::ty::context::tls::with_context_opt::<rustc_middle[a9ca1c3f9fd197cd]::ty::context::tls::with_opt<rustc_middle[a9ca1c3f9fd197cd]::util::bug::opt_span_bug_fmt<rustc_span[8f00505efff112e2]::span_encoding::Span>::{closure#0}, ()>::{closure#0}, ()>
  19:     0x7f77faab1c86 - rustc_middle[a9ca1c3f9fd197cd]::util::bug::opt_span_bug_fmt::<rustc_span[8f00505efff112e2]::span_encoding::Span>
  20:     0x7f77f844fa83 - rustc_middle[a9ca1c3f9fd197cd]::util::bug::bug_fmt
  21:     0x7f77faac76b2 - <rustc_middle[a9ca1c3f9fd197cd]::ty::subst::SubstFolder>::type_param_out_of_range
  22:     0x7f77f838a687 - <rustc_middle[a9ca1c3f9fd197cd]::ty::subst::SubstFolder as rustc_middle[a9ca1c3f9fd197cd]::ty::fold::TypeFolder>::fold_ty
  23:     0x560f724a2be8 - <&rustc_middle[a9ca1c3f9fd197cd]::ty::list::List<rustc_middle[a9ca1c3f9fd197cd]::ty::subst::GenericArg> as rustc_middle[a9ca1c3f9fd197cd]::ty::fold::TypeFoldable>::try_fold_with::<rustc_middle[a9ca1c3f9fd197cd]::ty::subst::SubstFolder>
  24:     0x560f7240a369 - <rustc_middle[a9ca1c3f9fd197cd]::ty::PredicateKind as rustc_middle[a9ca1c3f9fd197cd]::ty::fold::TypeFoldable>::try_fold_with::<rustc_middle[a9ca1c3f9fd197cd]::ty::subst::SubstFolder>
  25:     0x560f7249fb36 - <rustc_middle[a9ca1c3f9fd197cd]::ty::subst::SubstFolder as rustc_middle[a9ca1c3f9fd197cd]::ty::fold::FallibleTypeFolder>::try_fold_binder::<rustc_middle[a9ca1c3f9fd197cd]::ty::PredicateKind>
  26:     0x560f722e3630 - <core[8c92e53db3fc2eaa]::iter::adapters::copied::Copied<core[8c92e53db3fc2eaa]::slice::iter::Iter<rustc_middle[a9ca1c3f9fd197cd]::ty::Predicate>> as core[8c92e53db3fc2eaa]::iter::traits::iterator::Iterator>::try_fold::<(), core[8c92e53db3fc2eaa]::iter::adapters::filter::filter_try_fold<rustc_middle[a9ca1c3f9fd197cd]::ty::Predicate, (), core[8c92e53db3fc2eaa]::ops::control_flow::ControlFlow<()>, clippy_lints[641d7bf63abf0cc3]::methods::unnecessary_to_owned::can_change_type::{closure#5}, core[8c92e53db3fc2eaa]::iter::traits::iterator::Iterator::any::check<rustc_middle[a9ca1c3f9fd197cd]::ty::Predicate, clippy_lints[641d7bf63abf0cc3]::methods::unnecessary_to_owned::can_change_type::{closure#7}>::{closure#0}>::{closure#0}, core[8c92e53db3fc2eaa]::ops::control_flow::ControlFlow<()>>
  27:     0x560f72559d04 - clippy_lints[641d7bf63abf0cc3]::methods::unnecessary_to_owned::can_change_type
  28:     0x560f72558b5f - clippy_lints[641d7bf63abf0cc3]::methods::unnecessary_to_owned::check
  29:     0x560f72448d4b - <clippy_lints[641d7bf63abf0cc3]::methods::Methods as rustc_lint[dab68e85e8b6d341]::passes::LateLintPass>::check_expr
  30:     0x7f77fa83c954 - <rustc_lint[dab68e85e8b6d341]::early::EarlyLintPassObjects as rustc_lint[dab68e85e8b6d341]::passes::EarlyLintPass>::check_generic_arg
  31:     0x7f77f9b36643 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  32:     0x7f77f9b39305 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_expr::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  33:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  34:     0x7f77f9b39305 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_expr::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  35:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  36:     0x7f77f9b393e6 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_expr::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  37:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  38:     0x7f77f9b3933a - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_expr::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  39:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  40:     0x7f77f9b37fdb - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_local::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  41:     0x7f77f9b3681e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_local
  42:     0x7f77f9b37f8a - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_block::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  43:     0x7f77f9b36799 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_block
  44:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  45:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  46:     0x7f77f9b36799 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_block
  47:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  48:     0x7f77f9b36adc - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_body
  49:     0x7f77f9b36cd9 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_fn
  50:     0x7f77f9b39472 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_expr::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  51:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  52:     0x7f77f9b39305 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_expr::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  53:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  54:     0x7f77f9b36adc - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_body
  55:     0x7f77f9b36cd9 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_fn
  56:     0x7f77f9b3962d - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_item::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  57:     0x7f77f9b375de - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_item
  58:     0x7f77f9b37f8a - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_block::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  59:     0x7f77f9b36799 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_block
  60:     0x7f77f9b3664e - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_expr
  61:     0x7f77f9b36adc - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_body
  62:     0x7f77f9b36cd9 - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_fn
  63:     0x7f77f9b3962d - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_item::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  64:     0x7f77f9b375de - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_item
  65:     0x7f77f9b38f27 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_mod::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  66:     0x7f77f9b375de - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_item
  67:     0x7f77f9b38f27 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_mod::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  68:     0x7f77f9b375de - <rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects> as rustc_hir[f29014e7b3f8eb6c]::intravisit::Visitor>::visit_nested_item
  69:     0x7f77f9b38f27 - rustc_hir[f29014e7b3f8eb6c]::intravisit::walk_mod::<rustc_lint[dab68e85e8b6d341]::late::LateContextAndPass<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>>
  70:     0x7f77f9b36563 - rustc_lint[dab68e85e8b6d341]::late::late_lint_pass_crate::<rustc_lint[dab68e85e8b6d341]::late::LateLintPassObjects>
  71:     0x7f77f8deb511 - rustc_lint[dab68e85e8b6d341]::late::late_lint_crate::<rustc_lint[dab68e85e8b6d341]::BuiltinCombinedLateLintPass>
  72:     0x7f77f8de9ad6 - <rustc_session[c5946fac61f8bc34]::session::Session>::time::<(), rustc_lint[dab68e85e8b6d341]::late::check_crate<rustc_lint[dab68e85e8b6d341]::BuiltinCombinedLateLintPass, rustc_interface[3182dd864eff9d7d]::passes::analysis::{closure#5}::{closure#1}::{closure#2}::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>
  73:     0x7f77f8de99d9 - <rustc_session[c5946fac61f8bc34]::session::Session>::time::<(), rustc_interface[3182dd864eff9d7d]::passes::analysis::{closure#5}::{closure#1}::{closure#2}::{closure#0}>
  74:     0x7f77f8de97cf - <core[8c92e53db3fc2eaa]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[3182dd864eff9d7d]::passes::analysis::{closure#5}::{closure#1}> as core[8c92e53db3fc2eaa]::ops::function::FnOnce<()>>::call_once
  75:     0x7f77f8de8d9a - <rustc_session[c5946fac61f8bc34]::session::Session>::time::<(), rustc_interface[3182dd864eff9d7d]::passes::analysis::{closure#5}>
  76:     0x7f77f8de4cbc - rustc_interface[3182dd864eff9d7d]::passes::analysis
  77:     0x7f77f9843382 - <rustc_query_system[860ed7b39cdfb46b]::dep_graph::graph::DepGraph<rustc_middle[a9ca1c3f9fd197cd]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[a9ca1c3f9fd197cd]::ty::context::TyCtxt, (), core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>
  78:     0x7f77f9842a4a - rustc_query_system[860ed7b39cdfb46b]::query::plumbing::try_execute_query::<rustc_query_impl[d6191eea714bd250]::plumbing::QueryCtxt, rustc_query_system[860ed7b39cdfb46b]::query::caches::DefaultCache<(), core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>>
  79:     0x7f77f9842517 - rustc_query_system[860ed7b39cdfb46b]::query::plumbing::get_query::<rustc_query_impl[d6191eea714bd250]::queries::analysis, rustc_query_impl[d6191eea714bd250]::plumbing::QueryCtxt>
  80:     0x7f77f892e897 - <rustc_interface[3182dd864eff9d7d]::passes::QueryContext>::enter::<rustc_driver[cfb34b1539811fe8]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>
  81:     0x7f77f892228c - rustc_interface[3182dd864eff9d7d]::interface::create_compiler_and_run::<core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>, rustc_driver[cfb34b1539811fe8]::run_compiler::{closure#1}>
  82:     0x7f77f8920ac1 - <scoped_tls[e395fa6e23b19669]::ScopedKey<rustc_span[8f00505efff112e2]::SessionGlobals>>::set::<rustc_interface[3182dd864eff9d7d]::interface::run_compiler<core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>, rustc_driver[cfb34b1539811fe8]::run_compiler::{closure#1}>::{closure#0}, core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>
  83:     0x7f77f89207af - std[71cb4861428b0c25]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[3182dd864eff9d7d]::util::run_in_thread_pool_with_globals<rustc_interface[3182dd864eff9d7d]::interface::run_compiler<core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>, rustc_driver[cfb34b1539811fe8]::run_compiler::{closure#1}>::{closure#0}, core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>::{closure#0}, core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>
  84:     0x7f77f98d5d70 - <<std[71cb4861428b0c25]::thread::Builder>::spawn_unchecked_<rustc_interface[3182dd864eff9d7d]::util::run_in_thread_pool_with_globals<rustc_interface[3182dd864eff9d7d]::interface::run_compiler<core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>, rustc_driver[cfb34b1539811fe8]::run_compiler::{closure#1}>::{closure#0}, core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>::{closure#0}, core[8c92e53db3fc2eaa]::result::Result<(), rustc_errors[f77a66b68db622d5]::ErrorGuaranteed>>::{closure#1} as core[8c92e53db3fc2eaa]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  85:     0x7f77f724f003 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h49f797984e2121bf
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/alloc/src/boxed.rs:1940:9
  86:     0x7f77f724f003 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hfa4f3d0ee6440e0b
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/alloc/src/boxed.rs:1940:9
  87:     0x7f77f724f003 - std::sys::unix::thread::Thread::new::thread_start::h62ca48b42d48a8fc
                               at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/sys/unix/thread.rs:108:17
  88:     0x7f77f6ed0822 - start_thread
  89:     0x7f77f6e70450 - clone3
  90:                0x0 - <unknown>

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.65 (897e375 2022-11-02)

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack

[nickgerace]

Potentially related issue: #9746
(thanks for finding this, @fnichol)

[zacharyhamm]

Ok I got a minimal reproduction of this issue. With tokio version 1 (features = full):

async fn str_as_ref(a: impl AsRef<str>) {}

#[tokio::main]
async fn main() {
    str_as_ref("b".to_string()).await;
}

gives me:

$ cargo clippy
    Checking to_owned v0.1.0 (/Users/zacharyhamm/to_owned)
warning: unused variable: `a`
 --> src/main.rs:1:21
  |
1 | async fn str_as_ref(a: impl AsRef<str>) {}
  |                     ^ help: if this is intentional, prefix it with an underscore: `_a`
  |
  = note: `#[warn(unused_variables)]` on by default

error: internal compiler error: compiler/rustc_middle/src/ty/subst.rs:626:9: type parameter `Self/#0` (Self/0) out of range when substituting, substs=[]

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/897e37553bba8b42751c67658967889d11ecd120/compiler/rustc_errors/src/lib.rs:1462:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.65 (897e3755 2022-11-02)

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack
warning: `to_owned` (bin "to_owned") generated 1 warning
error: could not compile `to_owned`; 1 warning emitted

Here's the Cargo.toml:

[package]
name = "to_owned"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
tokio = { version = "1", features = ["full"] }

Edited to narrow down the issue further. Definitely only happens with the async fn.

Clippy version is:

clippy 0.1.65 (897e3755 2022-11-02)

What's interesting as well is that running the nightly clippy (clippy 0.1.66 (edf01822 2022-11-02)) does not show a lint at all for calling to_string on the argument passed to impl AsRef<str>:

warning: unused variable: `a`
 --> src/main.rs:1:21
  |
1 | async fn str_as_ref(a: impl AsRef<str>) {}
  |                     ^ help: if this is intentional, prefix it with an underscore: `_a`
  |
  = note: `#[warn(unused_variables)]` on by default

warning: `to_owned` (bin "to_owned") generated 1 warning
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s

[Porges]

Also hit this (see linked PR), I think invoking a fn(impl AsRef<Path>) from an async function (but I haven't looked deeply into it yet).

[Porges]

I tried adding a test on latest master using @zacharyhamm’s repro but it doesn’t seem to fail there.

[flip1995]

Duplicate of #9504

The fix for this hasn't made it to stable yet. From a quick check, it should be in beta and should get into 1.66 stable.