ICE getting discriminant of #[repr(i128)] enum

[durka]

ICE occurs whether we use intrinsics::discriminant_value or mem::discriminant. cc #35118 #24263

STR

#![feature(core_intrinsics)]
#![feature(i128_type)]

#[repr(i128)]
enum Big { A, B }

fn main() {
    unsafe {
        println!("{} {:?}",
            std::intrinsics::discriminant_value(&Big::A),
            std::mem::discriminant(&Big::B));
    }
}

ICE

thread 'rustc' panicked at 'assertion failed: bits <= 64', src/librustc_trans/adt.rs:368:4
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
   1: std::panicking::default_hook::{{closure}}
   2: std::panicking::default_hook
   3: std::panicking::rust_panic_with_hook
   4: std::panicking::begin_panic_new
   5: rustc_trans::adt::load_discr
   6: rustc_trans::adt::trans_get_discr
   7: rustc_trans::intrinsic::trans_intrinsic_call
   8: rustc_trans::mir::block::<impl rustc_trans::mir::MirContext<'a, 'tcx>>::trans_terminator
   9: rustc_trans::mir::trans_mir
  10: rustc_trans::trans_item::TransItem::define
  11: rustc_trans::base::trans_crate::module_translation
  12: rustc_trans::base::trans_crate
  13: rustc_driver::driver::phase_4_translate_to_llvm
  14: rustc_driver::driver::compile_input::{{closure}}
  15: rustc_driver::driver::phase_3_run_analysis_passes::{{closure}}
  16: rustc_driver::driver::phase_3_run_analysis_passes
  17: rustc_driver::driver::compile_input
  18: rustc_driver::run_compiler

[varkor]

The updated example no longer ICEs.

[jakubadamw]

@Mark-Simulacrum, this can be closed as it no longer ICEs.

[Mark-Simulacrum]

Actually, presumably, E-needstest.