thread 'rustc' panicked at 'no label after fn'

[psionic12]

Code

use std::cell::UnsafeCell;

struct Foo<T> {}

impl<T> Foo<T> {
    thread_local! {
        static TL: UnsafeCell<Vec<T>> = UnsafeCell::new(Vec::new());
    }
}

fn main() {}

Meta

rustc --version --verbose:

rustc 1.63.0 (4b91a6ea7 2022-08-08)
binary: rustc
commit-hash: 4b91a6ea7258a947e59c6522cd5898e7c0a6a88f
commit-date: 2022-08-08
host: x86_64-apple-darwin
release: 1.63.0
LLVM version: 14.0.5

Error output

/Users/x/.cargo/bin/cargo +stable build --color=always --message-format=json-diagnostic-rendered-ansi --package rust_hello_world --bin rust_hello_world
   Compiling rust_hello_world v0.1.0 (/Users/x/CLionProjects/rust_hello_world)
thread 'rustc' panicked at 'no label after fn', compiler/rustc_span/src/source_map.rs:972:18
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic_display
   3: core::panicking::panic_str
   4: core::option::expect_failed
   5: <rustc_span::source_map::SourceMap>::generate_fn_name_span
   6: <rustc_resolve::Resolver>::into_struct_error
   7: <rustc_resolve::Resolver>::report_error
   8: <rustc_resolve::Resolver>::resolve_ident_in_lexical_scope
   9: <rustc_resolve::Resolver>::resolve_path_with_ribs
  10: <rustc_resolve::late::LateResolutionVisitor>::smart_resolve_path_fragment
  11: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_ty
  12: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_generic_arg
  13: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_path_segment
  14: rustc_ast::visit::walk_ty::<rustc_resolve::late::LateResolutionVisitor>
  15: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_ty
  16: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_generic_arg
  17: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_path_segment
  18: rustc_ast::visit::walk_ty::<rustc_resolve::late::LateResolutionVisitor>
  19: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_ty
  20: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_fn
  21: rustc_ast::visit::walk_item::<rustc_resolve::late::LateResolutionVisitor>
  22: <rustc_resolve::late::LateResolutionVisitor>::resolve_item
  23: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_item
  24: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_block
  25: <rustc_resolve::late::LateResolutionVisitor>::resolve_expr
  26: <rustc_resolve::late::LateResolutionVisitor>::resolve_impl_item
  27: <rustc_resolve::late::LateResolutionVisitor>::resolve_item
  28: <rustc_resolve::late::LateResolutionVisitor as rustc_ast::visit::Visitor>::visit_item
  29: <rustc_resolve::Resolver>::late_resolve_crate
  30: <rustc_session::session::Session>::time::<(), <rustc_resolve::Resolver>::resolve_crate::{closure#0}>
  31: rustc_interface::passes::configure_and_expand
  32: <rustc_interface::queries::Queries>::expansion
  33: <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>>
  34: 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}>
  35: <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.
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 1.63.0 (4b91a6ea7 2022-08-08) running on x86_64-apple-darwin
note: compiler flags: --crate-type bin -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 `rust_hello_world`
Process finished with exit code 101

Backtrace

<backtrace>

[ChayimFriedman2]

Simpler reproduction:

struct Foo<T> {}

impl<T> Foo<T> {
    thread_local! {
        static TL: T = {};
    }
}

[Noratrieb]

I can't reproduce this on the latest nightly.

[TaKO8Ki]

I think #98609 fixed this problem.

[estebank]

These should be easy to fix. We need to change the expect with return None; in generate_local_type_param_snippet and generate_fn_name_span. We should also look at all the callers and replace them with alternatives, instead of synthesizing spans.

[TaKO8Ki]

@estebank I will work on this!

[cjgillot]

#99249 should fix it.