ICE "Found outer attribute Attribute..." with #[derive(thiserrror::Error)] and #[allow(..)]

[jgallagher]

Code

use thiserror::Error;

#![warn(single_use_lifetimes)] // not legal here, but the ICE disappears if this is moved above the `use`

#[derive(Error)]
#[allow(single_use_lifetimes)]
enum Foo {
    #[error("blah blah")]
    Bar,
}

Playground link: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=b149086e3735754ac70811ca05103814

This might be a dupe of #87936, but the combination of the #![warn(..)] placement and the fact that this is just using a proc macro led me to think it's possible it's different enough to be interesting.

Meta

rustc --version --verbose:

rustc 1.55.0 (c8dfcfe04 2021-09-06)
binary: rustc
commit-hash: c8dfcfe046a7680554bf4eb612bad840e7631c4b
commit-date: 2021-09-06
host: x86_64-apple-darwin
release: 1.55.0
LLVM version: 12.0.1

Also occurs in nightly:

rustc 1.57.0-nightly (9bb77da74 2021-09-13)
binary: rustc
commit-hash: 9bb77da74dac4768489127d21e32db19b59ada5b
commit-date: 2021-09-13
host: x86_64-apple-darwin
release: 1.57.0-nightly
LLVM version: 13.0.0

Error output

error: an inner attribute is not permitted in this context
 --> src/main.rs:3:1
  |
3 | #![warn(single_use_lifetimes)] // not legal here, but the ICE disappears if this is moved above the `use`
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.

thread 'rustc' panicked at 'Found outer attribute Attribute { kind: Normal(AttrItem { path: Path { span: src/main.rs:6:3: 6:8 (#0), segments: [PathSegment { ident: allow#0, id: NodeId(4294967040), args: None }], tokens: None }, args: Delimited(DelimSpan { open: src/main.rs:6:8: 6:9 (#0), close: src/main.rs:6:29: 6:30 (#0) }, Parenthesis, TokenStream([(Token(Token { kind: Ident("single_use_lifetimes", false), span: src/main.rs:6:9: 6:29 (#0) }), Alone)])), tokens: None }, Some(LazyTokenStream(AttrAnnotatedTokenStream([(Token(Token { kind: Pound, span: src/main.rs:6:1: 6:2 (#0) }), Alone), (Delimited(DelimSpan { open: src/main.rs:6:2: 6:3 (#0), close: src/main.rs:6:30: 6:31 (#0) }, Bracket, AttrAnnotatedTokenStream([(Token(Token { kind: Ident("allow", false), span: src/main.rs:6:3: 6:8 (#0) }), Alone), (Delimited(DelimSpan { open: src/main.rs:6:8: 6:9 (#0), close: src/main.rs:6:29: 6:30 (#0) }, Paren, AttrAnnotatedTokenStream([(Token(Token { kind: Ident("single_use_lifetimes", false), span: src/main.rs:6:9: 6:29 (#0) }), Alone)])), Alone)])), Alone)])))), id: AttrId(2), style: Outer, span: src/main.rs:6:1: 6:31 (#0) } after inner attrs [Attribute { kind: Normal(AttrItem { path: Path { span: src/main.rs:3:4: 3:8 (#0), segments: [PathSegment { ident: warn#0, id: NodeId(4294967040), args: None }], tokens: None }, args: Delimited(DelimSpan { open: src/main.rs:3:8: 3:9 (#0), close: src/main.rs:3:29: 3:30 (#0) }, Parenthesis, TokenStream([(Token(Token { kind: Ident("single_use_lifetimes", false), span: src/main.rs:3:9: 3:29 (#0) }), Alone)])), tokens: None }, Some(LazyTokenStream(AttrAnnotatedTokenStream([(Token(Token { kind: Pound, span: src/main.rs:3:1: 3:2 (#0) }), Joint), (Token(Token { kind: Not, span: src/main.rs:3:2: 3:3 (#0) }), Alone), (Delimited(DelimSpan { open: src/main.rs:3:3: 3:4 (#0), close: src/main.rs:3:30: 3:31 (#0) }, Bracket, AttrAnnotatedTokenStream([(Token(Token { kind: Ident("warn", false), span: src/main.rs:3:4: 3:8 (#0) }), Alone), (Delimited(DelimSpan { open: src/main.rs:3:8: 3:9 (#0), close: src/main.rs:3:29: 3:30 (#0) }, Paren, AttrAnnotatedTokenStream([(Token(Token { kind: Ident("single_use_lifetimes", false), span: src/main.rs:3:9: 3:29 (#0) }), Alone)])), Alone)])), Alone)])))), id: AttrId(0), style: Inner, span: src/main.rs:3:1: 3:31 (#0) }]', compiler/rustc_ast/src/tokenstream.rs:224:33

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 1.55.0 (c8dfcfe04 2021-09-06) running on x86_64-apple-darwin

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

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

query stack during panic:
end of query stack

Backtrace

stack backtrace:
   0: _rust_begin_unwind
   1: std::panicking::begin_panic_fmt
   2: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &mut F>::call_once
   3: <core::iter::adapters::flatten::FlatMap<I,U,F> as core::iter::traits::iterator::Iterator>::next
   4: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter::SpecFromIter<T,I>>::from_iter
   5: rustc_ast::tokenstream::AttrAnnotatedTokenStream::to_tokenstream
   6: rustc_parse::prepend_attrs
   7: rustc_parse::nt_to_tokenstream
   8: <rustc_expand::proc_macro::ProcMacroDerive as rustc_expand::base::MultiItemModifier>::expand
   9: rustc_expand::expand::MacroExpander::fully_expand_fragment
  10: rustc_expand::expand::MacroExpander::expand_crate
  11: rustc_session::utils::<impl rustc_session::session::Session>::time
  12: rustc_interface::passes::configure_and_expand
  13: rustc_interface::queries::Queries::expansion
  14: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  15: rustc_span::with_source_map
  16: rustc_interface::interface::create_compiler_and_run
  17: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[EliseZeroTwo]

This was fixed by #90267

[JohnTitor]

Triage: The above PR indeed fixed the issue and has a regression test, closing as fixed.