ICE with macro defining invalid enum that derives a trait

[cdmistman]

Code

macro_rules! values {
	($($token:ident($value:literal) $(as $inner:ty)? => $attr:meta,)*) => {
		#[derive(Debug)]
		pub enum TokenKind {
			$(
				#[$attr]
				$token $($inner)? = $value,
			)*
		}
	};
}

values!(STRING(1) as (String) => cfg(test),);

Meta

rustc --version --verbose:

rustc 1.62.0-nightly (4dd8b420c 2022-05-01)
binary: rustc
commit-hash: 4dd8b420c027001e47b0d811a7e55e2fe1de1395
commit-date: 2022-05-01
host: aarch64-apple-darwin
release: 1.62.0-nightly
LLVM version: 14.0.1

Error output

$ cargo check
    Checking repro v0.1.0 (/blah/crates/repro)
error: expected one of `(`, `,`, `=`, `{`, or `}`, found `(String)`
  --> crates/repro/src/lib.rs:7:14
   |
7  |                 $token $($inner)? = $value,
   |                          ^^^^^^ expected one of `(`, `,`, `=`, `{`, or `}`
...
13 | tokens!(STRING(1) as (String) => cfg(test),);
   | -------------------------------------------- in this macro invocation
   |
   = note: this error originates in the macro `tokens` (in Nightly builds, run with -Z macro-backtrace for more info)

error: macro expansion ignores token `(String)` and any following
  --> crates/repro/src/lib.rs:7:14
   |
7  |                 $token $($inner)? = $value,
   |                          ^^^^^^
...
13 | tokens!(STRING(1) as (String) => cfg(test),);
   | -------------------------------------------- caused by the macro expansion here
   |
   = note: the usage of `tokens!` is likely invalid in item context

thread 'rustc' panicked at 'Stack should be empty: final_buf=FrameData { open_delim_sp: Some((Brace, crates/repro/src/lib.rs:4:22: 9:4 (#4))), inner: [(Token(Token { kind: Pound, span: crates/repro/src/lib.rs:6:5: 6:6 (#4) }), Alone), (Delimited(DelimSpan { open: crates/repro/src/lib.rs:6:6: 6:7 (#4), close: crates/repro/src/lib.rs:6:12: 6:13 (#4) }, Bracket, AttrAnnotatedTokenStream([(Token(Token { kind: Interpolated(NtMeta(..)), span: crates/repro/src/lib.rs:6:7: 6:12 (#4) }), Alone)])), Alone), (Token(Token { kind: Interpolated(NtIdent(..)), span: crates/repro/src/lib.rs:7:5: 7:11 (#4) }), Alone)] } stack=[FrameData { open_delim_sp: None, inner: [(Token(Token { kind: Ident("pub", false), span: crates/repro/src/lib.rs:4:3: 4:6 (#4) }), Alone), (Token(Token { kind: Ident("enum", false), span: crates/repro/src/lib.rs:4:7: 4:11 (#4) }), Alone), (Token(Token { kind: Ident("TokenKind", false), span: crates/repro/src/lib.rs:4:12: 4:21 (#4) }), Alone)] }]', compiler/rustc_parse/src/parser/attr_wrapper.rs:500:5
stack backtrace:
   0:        0x1031cbe94 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h23e3041a952a3192
   1:        0x10321d790 - core::fmt::write::hf7527de7ada02621
   2:        0x1031beeb0 - std::io::Write::write_fmt::h11ac03f695ea0bfd
   3:        0x1031ceb94 - std::panicking::default_hook::{{closure}}::hbc68a212d51bb096
   4:        0x1031ce870 - std::panicking::default_hook::h8ba60dc6deb30472
   5:        0x10a4c95e4 - rustc_driver[be97d6212fff1111]::DEFAULT_HOOK::{closure#0}::{closure#0}
   6:        0x1031cf270 - std::panicking::rust_panic_with_hook::h9b549e34f7164858
   7:        0x1031cf0c8 - std::panicking::begin_panic_handler::{{closure}}::h50e8103cafb0a3d6
   8:        0x1031cc370 - std::sys_common::backtrace::__rust_end_short_backtrace::h7046937afbaad16d
   9:        0x1031cee20 - _rust_begin_unwind
  10:        0x10324bc88 - core::panicking::panic_fmt::h4ae2eb332ac288b3
  11:        0x10db35250 - <rustc_parse[6f970b7ceb167d01]::parser::attr_wrapper::LazyTokenStreamImpl as rustc_ast[5b6630b34daf7a2]::tokenstream::CreateTokenStream>::create_token_stream
  12:        0x10dadd228 - rustc_parse[6f970b7ceb167d01]::prepend_attrs
  13:        0x10dadc900 - rustc_parse[6f970b7ceb167d01]::nt_to_tokenstream
  14:        0x10c88fcc0 - rustc_builtin_macros[ce373b3deb6b848d]::cfg_eval::cfg_eval
  15:        0x10c885804 - <rustc_builtin_macros[ce373b3deb6b848d]::derive::Expander as rustc_expand[3645db8203ef6e1d]::base::MultiItemModifier>::expand::{closure#0}
  16:        0x10cb9f3e8 - <rustc_resolve[82457f197e93ce33]::Resolver as rustc_expand[3645db8203ef6e1d]::base::ResolverExpand>::resolve_derives
  17:        0x10c8854b4 - <rustc_builtin_macros[ce373b3deb6b848d]::derive::Expander as rustc_expand[3645db8203ef6e1d]::base::MultiItemModifier>::expand
  18:        0x10d993e2c - <rustc_expand[3645db8203ef6e1d]::expand::MacroExpander>::fully_expand_fragment
  19:        0x10d991e04 - <rustc_expand[3645db8203ef6e1d]::expand::MacroExpander>::expand_crate
  20:        0x10a5896e0 - <rustc_session[ae993a5043b66882]::session::Session>::time::<core[e4699273b2677591]::result::Result<rustc_ast[5b6630b34daf7a2]::ast::Crate, rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_interface[4ab8c5333806be77]::passes::configure_and_expand::{closure#1}>
  21:        0x10a584640 - rustc_interface[4ab8c5333806be77]::passes::configure_and_expand
  22:        0x10a605040 - <rustc_interface[4ab8c5333806be77]::queries::Queries>::expansion
  23:        0x10a475f48 - <rustc_interface[4ab8c5333806be77]::interface::Compiler>::enter::<rustc_driver[be97d6212fff1111]::run_compiler::{closure#1}::{closure#2}, core[e4699273b2677591]::result::Result<core[e4699273b2677591]::option::Option<rustc_interface[4ab8c5333806be77]::queries::Linker>, rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>>
  24:        0x10a4ce578 - rustc_span[595034ce2e7fee82]::with_source_map::<core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_interface[4ab8c5333806be77]::interface::create_compiler_and_run<core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_driver[be97d6212fff1111]::run_compiler::{closure#1}>::{closure#1}>
  25:        0x10a476634 - rustc_interface[4ab8c5333806be77]::interface::create_compiler_and_run::<core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_driver[be97d6212fff1111]::run_compiler::{closure#1}>
  26:        0x10a470b6c - <scoped_tls[8a4b2aa1592938bb]::ScopedKey<rustc_span[595034ce2e7fee82]::SessionGlobals>>::set::<rustc_interface[4ab8c5333806be77]::interface::run_compiler<core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_driver[be97d6212fff1111]::run_compiler::{closure#1}>::{closure#0}, core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>>
  27:        0x10a4bc8b4 - std[6fb83afb07978576]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[4ab8c5333806be77]::util::run_in_thread_pool_with_globals<rustc_interface[4ab8c5333806be77]::interface::run_compiler<core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_driver[be97d6212fff1111]::run_compiler::{closure#1}>::{closure#0}, core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>>::{closure#0}, core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>>
  28:        0x10a4961d0 - <<std[6fb83afb07978576]::thread::Builder>::spawn_unchecked_<rustc_interface[4ab8c5333806be77]::util::run_in_thread_pool_with_globals<rustc_interface[4ab8c5333806be77]::interface::run_compiler<core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>, rustc_driver[be97d6212fff1111]::run_compiler::{closure#1}>::{closure#0}, core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>>::{closure#0}, core[e4699273b2677591]::result::Result<(), rustc_errors[6fdaf2daf3d0fd37]::ErrorGuaranteed>>::{closure#1} as core[e4699273b2677591]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  29:        0x1031d7b40 - std::sys::unix::thread::Thread::new::thread_start::h4b803e136338a26a
  30:        0x19718226c - __pthread_deallocate

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 1.62.0-nightly (4dd8b420c 2022-05-01) running on aarch64-apple-darwin

note: compiler flags: --crate-type lib -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack
error: could not compile `repro` due to 2 previous errors

Backtrace

$ RUST_BACKTRACE=1 cargo check
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: <rustc_parse::parser::attr_wrapper::LazyTokenStreamImpl as rustc_ast::tokenstream::CreateTokenStream>::create_token_stream
   3: rustc_parse::prepend_attrs
   4: rustc_parse::nt_to_tokenstream
   5: rustc_builtin_macros::cfg_eval::cfg_eval
   6: <rustc_builtin_macros::derive::Expander as rustc_expand::base::MultiItemModifier>::expand::{closure#0}
   7: <rustc_resolve::Resolver as rustc_expand::base::ResolverExpand>::resolve_derives
   8: <rustc_builtin_macros::derive::Expander as rustc_expand::base::MultiItemModifier>::expand
   9: <rustc_expand::expand::MacroExpander>::fully_expand_fragment
  10: <rustc_expand::expand::MacroExpander>::expand_crate
  11: <rustc_session::session::Session>::time::<core::result::Result<rustc_ast::ast::Crate, rustc_errors::ErrorGuaranteed>, rustc_interface::passes::configure_and_expand::{closure#1}>
  12: rustc_interface::passes::configure_and_expand
  13: <rustc_interface::queries::Queries>::expansion
  14: <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::ErrorGuaranteed>>
  15: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#1}>
  16: rustc_interface::interface::create_compiler_and_run::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>
  17: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[hellow554]

Probably a duplicate of #81920

[hellow554]

Quick question: is this a real world code or just messing around? Because the other one was found using a fuzzer which produces some code and is typically not a high priority.
If your code is from some code you wrote, the priority might be increased.

[cdmistman]

It's for a single-use DSL macro I defined in a prototype tokenizer I'm working on. Since type-defining DSLs are generally considered an anti-pattern, I'll point out syn seems to do the same