$ rustc bug.rs error: mismatched closing delimiter: `)` --> bug.rs:1:35 | 1 | macro_rules!test{($l:expr,$_:r)=>({const:y y)} | -^ ^ mismatched closing delimiter | || | |unclosed delimiter | closing delimiter possibly meant for this error: invalid fragment specifier `r` --> bug.rs:1:27 | 1 | macro_rules!test{($l:expr,$_:r)=>({const:y y)} | ^^^^ | = help: valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, `item` and `vis` error: expected identifier, found keyword `const` --> bug.rs:1:36 | 1 | macro_rules!test{($l:expr,$_:r)=>({const:y y)} | ^^^^^ expected identifier, found keyword 2 | 3 | fn s(){test!(1,i)} | ---------- in this macro invocation | = note: this error originates in the macro `test` (in Nightly builds, run with -Z macro-backtrace for more info) help: escape `const` to use it as an identifier | 1 | macro_rules!test{($l:expr,$_:r)=>({r#const:y y)} | ++ thread 'rustc' panicked at 'expected non-translatable diagnostic message', compiler/rustc_error_messages/src/lib.rs:349:18 stack backtrace: 0: 0x7fa3a076c460 - std::backtrace_rs::backtrace::libunwind::trace::hab36ac9237175c04 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 1: 0x7fa3a076c460 - std::backtrace_rs::backtrace::trace_unsynchronized::h1564f1268a5216f0 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 2: 0x7fa3a076c460 - std::sys_common::backtrace::_print_fmt::hac27c34a5b2f4ffb at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/sys_common/backtrace.rs:66:5 3: 0x7fa3a076c460 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h465811d7c5d92b76 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/sys_common/backtrace.rs:45:22 4: 0x7fa3a07c842e - core::fmt::write::h54cba5d5c8d6dce9 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/core/src/fmt/mod.rs:1209:17 5: 0x7fa3a075c645 - std::io::Write::write_fmt::h50cc62d6ddf5e7e8 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/io/mod.rs:1679:15 6: 0x7fa3a076f203 - std::sys_common::backtrace::_print::h0cea32817bcb8d62 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/sys_common/backtrace.rs:48:5 7: 0x7fa3a076f203 - std::sys_common::backtrace::print::h6bea8d931fa08f99 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/sys_common/backtrace.rs:35:9 8: 0x7fa3a076f203 - std::panicking::default_hook::{{closure}}::h43a7ba33989c8022 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/panicking.rs:267:22 9: 0x7fa3a076eeda - std::panicking::default_hook::hcf767613975331ea at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/panicking.rs:286:9 10: 0x7fa3a30b2481 - rustc_driver[237e7e66a4131160]::DEFAULT_HOOK::{closure#0}::{closure#0} 11: 0x7fa3a076fa3b - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h57ecc49ea7a84529 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/alloc/src/boxed.rs:1952:9 12: 0x7fa3a076fa3b - std::panicking::rust_panic_with_hook::ha9eb3b9804e3ced0 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/panicking.rs:673:13 13: 0x7fa3a076f851 - std::panicking::begin_panic_handler::{{closure}}::h64ee9f3bda89f283 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/panicking.rs:558:13 14: 0x7fa3a076c90c - std::sys_common::backtrace::__rust_end_short_backtrace::hebc6b64e793da45f at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/sys_common/backtrace.rs:138:18 15: 0x7fa3a076f5b2 - rust_begin_unwind at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/panicking.rs:556:5 16: 0x7fa3a07c5003 - core::panicking::panic_fmt::ha04a4224b9300698 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/core/src/panicking.rs:142:14 17: 0x7fa3a42a77ef - <rustc_error_messages[b7722f0beb847c22]::DiagnosticMessage>::expect_str 18: 0x7fa3a24869a4 - <rustc_expand[99b4c1a0d393d44f]::mbe::macro_rules::ParserAnyMacro>::make 19: 0x7fa3a2fe34dd - <rustc_expand[99b4c1a0d393d44f]::mbe::macro_rules::ParserAnyMacro as rustc_expand[99b4c1a0d393d44f]::base::MacResult>::make_expr 20: 0x7fa3a2749992 - <rustc_expand[99b4c1a0d393d44f]::expand::MacroExpander>::fully_expand_fragment 21: 0x7fa3a1d927c3 - <rustc_expand[99b4c1a0d393d44f]::expand::MacroExpander>::expand_crate 22: 0x7fa3a1d919a0 - <rustc_session[2b1647d71bfc4162]::session::Session>::time::<core[2f45054cb0339e39]::result::Result<rustc_ast[ea39079b98d97005]::ast::Crate, rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_interface[68feece4527b990]::passes::configure_and_expand::{closure#1}> 23: 0x7fa3a1d5ca53 - rustc_interface[68feece4527b990]::passes::configure_and_expand 24: 0x7fa3a1d56085 - <rustc_interface[68feece4527b990]::queries::Queries>::expansion 25: 0x7fa3a1d53d0c - <rustc_interface[68feece4527b990]::interface::Compiler>::enter::<rustc_driver[237e7e66a4131160]::run_compiler::{closure#1}::{closure#2}, core[2f45054cb0339e39]::result::Result<core[2f45054cb0339e39]::option::Option<rustc_interface[68feece4527b990]::queries::Linker>, rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>> 26: 0x7fa3a1d4ee4c - rustc_span[264e770df865a5e1]::with_source_map::<core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_interface[68feece4527b990]::interface::create_compiler_and_run<core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_driver[237e7e66a4131160]::run_compiler::{closure#1}>::{closure#1}> 27: 0x7fa3a1d4e84f - rustc_interface[68feece4527b990]::interface::create_compiler_and_run::<core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_driver[237e7e66a4131160]::run_compiler::{closure#1}> 28: 0x7fa3a1d4dc92 - <scoped_tls[eac668962b7404b4]::ScopedKey<rustc_span[264e770df865a5e1]::SessionGlobals>>::set::<rustc_interface[68feece4527b990]::interface::run_compiler<core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_driver[237e7e66a4131160]::run_compiler::{closure#1}>::{closure#0}, core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>> 29: 0x7fa3a1d4d97f - std[ea69dece37053cb8]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[68feece4527b990]::util::run_in_thread_pool_with_globals<rustc_interface[68feece4527b990]::interface::run_compiler<core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_driver[237e7e66a4131160]::run_compiler::{closure#1}>::{closure#0}, core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>>::{closure#0}, core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>> 30: 0x7fa3a2ec6ca0 - <<std[ea69dece37053cb8]::thread::Builder>::spawn_unchecked_<rustc_interface[68feece4527b990]::util::run_in_thread_pool_with_globals<rustc_interface[68feece4527b990]::interface::run_compiler<core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>, rustc_driver[237e7e66a4131160]::run_compiler::{closure#1}>::{closure#0}, core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>>::{closure#0}, core[2f45054cb0339e39]::result::Result<(), rustc_errors[c29306613d1e9c09]::ErrorGuaranteed>>::{closure#1} as core[2f45054cb0339e39]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 31: 0x7fa3a0779643 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h569d106cfed3b1a5 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/alloc/src/boxed.rs:1938:9 32: 0x7fa3a0779643 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::ha784c779129e61fe at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/alloc/src/boxed.rs:1938:9 33: 0x7fa3a0779643 - std::sys::unix::thread::Thread::new::thread_start::h4108e49084be78e5 at /rustc/81f391930301afbc121b7c468138069daa354bf8/library/std/src/sys/unix/thread.rs:108:17 34: 0x7fa3a0494b43 - start_thread at ./nptl/./nptl/pthread_create.c:442:8 35: 0x7fa3a0526a00 - clone3 at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 36: 0x0 - <unknown> 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 1.66.0-nightly (81f391930 2022-10-09) running on x86_64-unknown-linux-gnu query stack during panic: end of query stack error: aborting due to 3 previous errors