Closed as duplicate of#140479
Description
Code
macro_rules! foo {
($($($arg_type:ident),*),*) => {
$(
$(
${concat(le_, $arg_type)}
)*
)*
};
}
foo!(u32);Meta
rustc --version --verbose:
rustc 1.90.0-nightly (2a023bf80 2025-07-10)
binary: rustc
commit-hash: 2a023bf80a6fbd6a06d5460a34eb247b986286ed
commit-date: 2025-07-10
host: x86_64-unknown-linux-gnu
release: 1.90.0-nightly
LLVM version: 20.1.7
Error output
thread 'rustc' panicked at compiler/rustc_expand/src/mbe/transcribe.rs:559:46:
not implemented
stack backtrace:
0: 0x7f243279d815 - std::backtrace::Backtrace::create::h402d5dee4ff3ff4a
1: 0x7f243279d765 - std::backtrace::Backtrace::force_capture::hc053cd276d2dd0cf
2: 0x7f243185618e - std[3d755e9610f7e251]::panicking::update_hook::<alloc[7f4c2d72f38b8d7e]::boxed::Box<rustc_driver_impl[63982ee25ad4258]::install_ice_hook::{closure#1}>>::{closure#0}
3: 0x7f24327b77fe - std::panicking::rust_panic_with_hook::h95fdb0db127e3393
4: 0x7f24327b74c6 - std::panicking::begin_panic_handler::{{closure}}::h60a8d1dd28fdf2f9
5: 0x7f24327b3b79 - std::sys::backtrace::__rust_end_short_backtrace::h257feb614e80fbd3
6: 0x7f24327b71dd - __rustc[c00c44d2e7a9f37a]::rust_begin_unwind
7: 0x7f242eee32c0 - core::panicking::panic_fmt::h34a2576cfcb88dba
8: 0x7f242f3a1acc - core::panicking::panic::hccd196a068931ae7
9: 0x7f243466823a - <rustc_expand[e56076fee33d55f5]::expand::MacroExpander>::fully_expand_fragment
10: 0x7f243461c3f9 - <rustc_expand[e56076fee33d55f5]::expand::MacroExpander>::expand_crate
11: 0x7f2433acd02c - rustc_interface[ca8d5c69dfd7f14d]::passes::configure_and_expand
12: 0x7f24341d3963 - rustc_interface[ca8d5c69dfd7f14d]::passes::resolver_for_lowering_raw
13: 0x7f24341d36cd - rustc_query_impl[73f7b85c6196fc58]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[73f7b85c6196fc58]::query_impl::resolver_for_lowering_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[bfb8074addc0df29]::query::erase::Erased<[u8; 16usize]>>
14: 0x7f24341d36a7 - <rustc_query_impl[73f7b85c6196fc58]::query_impl::resolver_for_lowering_raw::dynamic_query::{closure#2} as core[557129ac99d5593e]::ops::function::FnOnce<(rustc_middle[bfb8074addc0df29]::ty::context::TyCtxt, ())>>::call_once
15: 0x7f2434421f29 - rustc_query_system[9ad56969e99527f5]::query::plumbing::try_execute_query::<rustc_query_impl[73f7b85c6196fc58]::DynamicConfig<rustc_query_system[9ad56969e99527f5]::query::caches::SingleCache<rustc_middle[bfb8074addc0df29]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[73f7b85c6196fc58]::plumbing::QueryCtxt, true>
16: 0x7f2434421941 - rustc_query_impl[73f7b85c6196fc58]::query_impl::resolver_for_lowering_raw::get_query_incr::__rust_end_short_backtrace
17: 0x7f24343191c0 - rustc_interface[ca8d5c69dfd7f14d]::passes::create_and_enter_global_ctxt::<core[557129ac99d5593e]::option::Option<rustc_interface[ca8d5c69dfd7f14d]::queries::Linker>, rustc_driver_impl[63982ee25ad4258]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
18: 0x7f2434228f17 - rustc_interface[ca8d5c69dfd7f14d]::interface::run_compiler::<(), rustc_driver_impl[63982ee25ad4258]::run_compiler::{closure#0}>::{closure#1}
19: 0x7f24341e52f8 - std[3d755e9610f7e251]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[ca8d5c69dfd7f14d]::util::run_in_thread_with_globals<rustc_interface[ca8d5c69dfd7f14d]::util::run_in_thread_pool_with_globals<rustc_interface[ca8d5c69dfd7f14d]::interface::run_compiler<(), rustc_driver_impl[63982ee25ad4258]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
20: 0x7f24341e4fd6 - <<std[3d755e9610f7e251]::thread::Builder>::spawn_unchecked_<rustc_interface[ca8d5c69dfd7f14d]::util::run_in_thread_with_globals<rustc_interface[ca8d5c69dfd7f14d]::util::run_in_thread_pool_with_globals<rustc_interface[ca8d5c69dfd7f14d]::interface::run_compiler<(), rustc_driver_impl[63982ee25ad4258]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[557129ac99d5593e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
21: 0x7f24341eaebd - std::sys::pal::unix::thread::Thread::new::thread_start::h94d994b2c0a286ed
22: 0x7f242daa57eb - <unknown>
23: 0x7f242db2918c - <unknown>
24: 0x0 - <unknown>
rustc version: 1.90.0-nightly (2a023bf80 2025-07-10)
platform: x86_64-unknown-linux-gnu
query stack during panic:
#0 [resolver_for_lowering_raw] getting the resolver for lowering
end of query stack
Backtrace
Compiling touhou-formats v0.1.0 (/home/linkmauve/packages/pytouhou-hg/src/pytouhou/formats)
error[E0658]: the `concat` meta-variable expression is unstable
--> formats/src/th06/anm0.rs:5:18
|
5 | ${concat(le_, $arg_type)}
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #124225 <https://github.com/rust-lang/rust/issues/124225> for more information
= help: add `#![feature(macro_metavar_expr_concat)]` to the crate attributes to enable
= note: this compiler was built on 2025-07-10; consider upgrading it if it is out of date
thread 'rustc' panicked at compiler/rustc_expand/src/mbe/transcribe.rs:559:46:
not implemented
stack backtrace:
0: __rustc::rust_begin_unwind
1: core::panicking::panic_fmt
2: core::panicking::panic
3: <rustc_expand::expand::MacroExpander>::fully_expand_fragment
4: <rustc_expand::expand::MacroExpander>::expand_crate
5: rustc_interface::passes::configure_and_expand
6: rustc_interface::passes::resolver_for_lowering_raw
[... omitted 2 frames ...]
7: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
8: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
error: 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: please make sure that you have updated to the latest nightly
note: please attach the file at `/home/linkmauve/packages/pytouhou-hg/src/pytouhou/rustc-ice-2025-07-11T23_30_59-1699990.txt` to your bug report
note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2 -C linker=clang -C incremental=[REDACTED] -C target-cpu=native
note: some of the compiler flags provided by cargo are hidden
query stack during panic:
#0 [resolver_for_lowering_raw] getting the resolver for lowering
end of query stack
For more information about this error, try `rustc --explain E0658`.
error: could not compile `touhou-formats` (lib) due to 1 previous error