Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
already borrowed: BorrowMutError
stack backtrace:
   0:     0x7fff8f5d0de8 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h358da5a7e33a66e2
   1:     0x7fff8ed5b838 - core::fmt::write::h6bc2db31dd03e7df
   2:     0x7fff8f5bec44 - <unknown>
   3:     0x7fff8f5d0be4 - <unknown>
   4:     0x7fff8f5d41a4 - <unknown>
   5:     0x7fff8f5d3b50 - std::panicking::default_hook::hc8100c38be18401f
   6:     0x7fff8c1a0b6c - <unknown>
   7:     0x7fff8c171530 - <unknown>
   8:     0x7fff8f5d50a8 - std::panicking::rust_panic_with_hook::hb454b0dcbf5fc939
   9:     0x7fff8f5d4b38 - <unknown>
  10:     0x7fff8f5d14b0 - std::sys::backtrace::__rust_end_short_backtrace::h03d44392342f1184
  11:     0x7fff8f5d4584 - __rustc[c2610c6383308acc]::rust_begin_unwind
  12:     0x7fff8b9b9414 - core::panicking::panic_fmt::hf33b6b3da6dfe6bc
  13:     0x7fff8b9b9278 - core::cell::panic_already_borrowed::h59a581a7b2415564
  14:     0x7fff8d97f280 - <rustc_borrowck[ff17395deed2ec8e]::type_check::TypeChecker as rustc_middle[687e2f65837ea9de]::mir::visit::Visitor>::visit_body
  15:     0x7fff8d8e3f5c - <unknown>
  16:     0x7fff8d8adac0 - <unknown>
  17:     0x7fff8d9dbf10 - <unknown>
  18:     0x7fff8e92d7a8 - <unknown>
  19:     0x7fff8e8c9adc - rustc_query_system[9f00eb678419a2a2]::query::plumbing::try_execute_query::<rustc_query_impl[4578bb995ede35ef]::DynamicConfig<rustc_data_structures[7e0816562978da6d]::vec_cache::VecCache<rustc_span[c8935130265359c6]::def_id::LocalDefId, rustc_middle[687e2f65837ea9de]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[9f00eb678419a2a2]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[4578bb995ede35ef]::plumbing::QueryCtxt, false>
  20:     0x7fff8e950d04 - <unknown>
  21:     0x7fff8e0a7690 - <unknown>
  22:     0x7fff8f11feac - rustc_interface[537fa850fc24b132]::passes::analysis
  23:     0x7fff8f3bf39c - <unknown>
  24:     0x7fff8f30d844 - rustc_query_system[9f00eb678419a2a2]::query::plumbing::try_execute_query::<rustc_query_impl[4578bb995ede35ef]::DynamicConfig<rustc_query_system[9f00eb678419a2a2]::query::caches::SingleCache<rustc_middle[687e2f65837ea9de]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[4578bb995ede35ef]::plumbing::QueryCtxt, false>
  25:     0x7fff8f3c6238 - <unknown>
  26:     0x7fff8efb43ac - <unknown>
  27:     0x7fff8efb0594 - <unknown>
  28:     0x7fff8efac588 - std[8587342a5b72dfb4]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[537fa850fc24b132]::util::run_in_thread_with_globals<rustc_interface[537fa850fc24b132]::util::run_in_thread_pool_with_globals<rustc_interface[537fa850fc24b132]::interface::run_compiler<(), rustc_driver_impl[d9b811d677f6ce88]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  29:     0x7fff8efb7c54 - <unknown>
  30:     0x7fff8f5dc5c8 - <unknown>
  31:     0x7fff8aeb693c - start_thread
  32:     0x7fff8af63908 - __clone3
error: the compiler unexpectedly panicked. this is a bug.

Answer: Compile issue