ICE internal error: entered unreachable code visitor.rs

[matthiaskrgr]

trait Trait {
    fn foo(&self) -> u32 { 0 }
}

struct F;

impl Trait for S {
    reuse to_reuse::foo { self }
    reuse <F as Trait>::foo;
}

rustfmt 1.7.0-nightly (7ffc697 2024-01-24)

thread 'main' panicked at src/tools/rustfmt/src/visitor.rs:674:18:
internal error: entered unreachable code
stack backtrace:
   0:     0x7fc73d42be86 - std::backtrace_rs::backtrace::libunwind::trace::h65dcfe0719cb4191
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7fc73d42be86 - std::backtrace_rs::backtrace::trace_unsynchronized::h4bc41f6b71b06b7a
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fc73d42be86 - std::sys_common::backtrace::_print_fmt::h60c6f19a391ed5dc
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7fc73d42be86 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h1740aea989e54934
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fc73d47e740 - core::fmt::rt::Argument::fmt::heb4dd44c49f74b16
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/core/src/fmt/rt.rs:142:9
   5:     0x7fc73d47e740 - core::fmt::write::h50d3db56423ee6d9
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/core/src/fmt/mod.rs:1120:17
   6:     0x7fc73d41f84f - std::io::Write::write_fmt::hd452428cb27ad2ee
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/io/mod.rs:1810:15
   7:     0x7fc73d42bc64 - std::sys_common::backtrace::_print::h320a7f6668a2f2da
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7fc73d42bc64 - std::sys_common::backtrace::print::hc3deb3f523c9c62a
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7fc73d42e9f7 - std::panicking::default_hook::{{closure}}::h785f274313249010
  10:     0x7fc73d42e759 - std::panicking::default_hook::haf9862715dd397f9
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:292:9
  11:     0x7fc73a14c99c - std[bfcaba45ac95563e]::panicking::update_hook::<alloc[8ea4dcc019e99709]::boxed::Box<rustc_driver_impl[385ba20d6b752673]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7fc73d42f146 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hb17665c06c8a6aea
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/alloc/src/boxed.rs:2030:9
  13:     0x7fc73d42f146 - std::panicking::rust_panic_with_hook::h8e4b0da96c90e358
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:785:13
  14:     0x7fc73d42ee59 - std::panicking::begin_panic_handler::{{closure}}::h1acf90bacec3e9e1
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:651:13
  15:     0x7fc73d42c386 - std::sys_common::backtrace::__rust_end_short_backtrace::h824689dc556a7ab2
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7fc73d42ebe4 - rust_begin_unwind
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:647:5
  17:     0x7fc73d47ae45 - core::panicking::panic_fmt::h021009ee6f01eba5
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/core/src/panicking.rs:72:14
  18:     0x7fc73d47af03 - core::panicking::panic::hbf1fe34e079bf0aa
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/core/src/panicking.rs:144:5
  19:     0x55640ce5691a - <rustfmt_nightly[b15dc3e924fa1352]::visitor::FmtVisitor>::visit_assoc_item
  20:     0x55640ce5bef4 - <rustfmt_nightly[b15dc3e924fa1352]::visitor::FmtVisitor>::with_context::<<rustfmt_nightly[b15dc3e924fa1352]::visitor::FmtVisitor>::visit_item::{closure#0}>
  21:     0x55640ce557bb - <rustfmt_nightly[b15dc3e924fa1352]::visitor::FmtVisitor>::visit_item
  22:     0x55640ce38a69 - <rustfmt_nightly[b15dc3e924fa1352]::visitor::FmtVisitor>::visit_items_with_reordering
  23:     0x55640ce597fb - <rustfmt_nightly[b15dc3e924fa1352]::visitor::FmtVisitor>::format_separate_mod
  24:     0x55640ccca232 - <rustfmt_nightly[b15dc3e924fa1352]::Session<std[bfcaba45ac95563e]::io::stdio::Stdout>>::format_input_inner::{closure#0}
  25:     0x55640cce0477 - rustfmt[4f1f2b051c0c3a3e]::format_and_emit_report::<std[bfcaba45ac95563e]::io::stdio::Stdout>
  26:     0x55640ccdec44 - rustfmt[4f1f2b051c0c3a3e]::execute
  27:     0x55640ccd9d14 - rustfmt[4f1f2b051c0c3a3e]::main
  28:     0x55640ccc3bf3 - std[bfcaba45ac95563e]::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>
  29:     0x55640ccc5de9 - std[bfcaba45ac95563e]::rt::lang_start::<()>::{closure#0}
  30:     0x7fc73d40fff1 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h389c4eb12d80bd7a
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/core/src/ops/function.rs:284:13
  31:     0x7fc73d40fff1 - std::panicking::try::do_call::h52e77b4ed8af2089
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:554:40
  32:     0x7fc73d40fff1 - std::panicking::try::hb5f9ac1d853ae913
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:518:19
  33:     0x7fc73d40fff1 - std::panic::catch_unwind::h8a97a2bd6b461080
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panic.rs:142:14
  34:     0x7fc73d40fff1 - std::rt::lang_start_internal::{{closure}}::h69577ea4d6906c00
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/rt.rs:148:48
  35:     0x7fc73d40fff1 - std::panicking::try::do_call::hb02fe2faabc7bb65
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:554:40
  36:     0x7fc73d40fff1 - std::panicking::try::h0237f38e141ac74e
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panicking.rs:518:19
  37:     0x7fc73d40fff1 - std::panic::catch_unwind::hc1b6eb273118c749
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/panic.rs:142:14
  38:     0x7fc73d40fff1 - std::rt::lang_start_internal::h6acc28113b76b5ad
                               at /rustc/5bd5d214effd494f4bafb29b3a7a2f6c2070ca5c/library/std/src/rt.rs:148:20
  39:     0x55640cce16a5 - main
  40:     0x7fc737158cd0 - <unknown>
  41:     0x7fc737158d8a - __libc_start_main
  42:     0x55640ccb3189 - <unknown>
  43:                0x0 - <unknown>

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

note: we would appreciate a bug report: https://github.com/rust-lang/rustfmt/issues/new?labels=bug

note: please attach the file at `/home/matthias/vcs/github/glacier2/fixed/rustc-ice-2024-01-25T17_36_49-1858855.txt` to your bug report

query stack during panic:
end of query stack

[ytmimi]

@matthiaskrgr what is reuse?

[matthiaskrgr]

I guess its part of fn delegation https://github.com/rust-lang/rust/blame/master/compiler/rustc_span/src/symbol.rs#L105

[ytmimi]

Yeah, I think you're right. I'm pretty sure we don't handle the new ast::AssocItemKind::Delegation variant.

[ytmimi]

Pretty sure this is where we hit the panic!:

rustfmt/src/visitor.rs

Lines 632 to 671 in bf96731

	match (&ai.kind, visitor_kind) {
	(ast::AssocItemKind::Const(..), AssocTraitItem(_)) => {
	self.visit_static(&StaticParts::from_trait_item(ai))
	}
	(ast::AssocItemKind::Const(..), AssocImplItem(_)) => {
	self.visit_static(&StaticParts::from_impl_item(ai))
	}
	(ast::AssocItemKind::Fn(ref fn_kind), _) => {
	let ast::Fn {
	defaultness,
	ref sig,
	ref generics,
	ref body,
	} = **fn_kind;
	if let Some(ref body) = body {
	let inner_attrs = inner_attributes(&ai.attrs);
	let fn_ctxt = visit::FnCtxt::Assoc(assoc_ctxt);
	self.visit_fn(
	visit::FnKind::Fn(fn_ctxt, ai.ident, sig, &ai.vis, generics, Some(body)),
	&sig.decl,
	ai.span,
	defaultness,
	Some(&inner_attrs),
	);
	} else {
	let indent = self.block_indent;
	let rewrite =
	self.rewrite_required_fn(indent, ai.ident, sig, &ai.vis, generics, ai.span);
	self.push_rewrite(ai.span, rewrite);
	}
	}
	(ast::AssocItemKind::Type(ref ty_alias), _) => {
	self.visit_ty_alias_kind(ty_alias, visitor_kind, ai.span);
	}
	(ast::AssocItemKind::MacCall(ref mac), _) => {
	self.visit_mac(mac, Some(ai.ident), MacroPosition::Item);
	}
	_ => unreachable!(),
	}
	}

We'll likely need to wait until the next subtree sync before a fix can be released for this