miri: invalid enum discriminant value read

[bjorn3]

When running it with priroda, the value for which the discriminant is read is 0xff

---- [ui] run-pass/issue-15523-big.rs stdout ----
	normalized stderr:
error[E0080]: constant evaluation error
  --> $DIR/issue-15523-big.rs:17:21
   |
17 | #[derive(PartialEq, PartialOrd)]
   |                     ^^^^^^^^^^ invalid enum discriminant value read
   |
note: inside call to `<Eu64 as std::cmp::PartialOrd>::partial_cmp`
  --> /home/bjorn/Documenten/rust2/src/libcore/cmp.rs:647:15
   |
647|         match self.partial_cmp(other) {
   |               ^^^^^^^^^^^^^^^^^^^^^^^
note: inside call to `<Eu64 as std::cmp::PartialOrd>::lt`
  --> $DIR/issue-15523-big.rs:37:13
   |
37 |     assert!(Eu64::Pos2 < Eu64::PosMax);
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
note: inside call to `main`
  --> /home/bjorn/Documenten/rust2/src/libstd/rt.rs:74:34
   |
74 |     lang_start_internal(&move || main().report(), argc, argv)
   |                                  ^^^^^^
note: inside call to `closure`
  --> /home/bjorn/Documenten/rust2/src/libstd/rt.rs:59:75
   |
59 |             ::sys_common::backtrace::__rust_begin_short_backtrace(move || main())
   |                                                                           ^^^^^^
note: inside call to `closure`
  --> /home/bjorn/Documenten/rust2/src/libstd/sys_common/backtrace.rs:136:5
   |
136|     f()
   |     ^^^
note: inside call to `std::sys_common::backtrace::__rust_begin_short_backtrace::<[closure@DefId(1/1:1802 ~ std[a0b6]::rt[0]::lang_start_internal[0]::{{closure}}[0]::{{closure}}[0]) 0:&std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>`
  --> /home/bjorn/Documenten/rust2/src/libstd/rt.rs:59:13
   |
59 |             ::sys_common::backtrace::__rust_begin_short_backtrace(move || main())
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: inside call to `closure`
  --> /home/bjorn/Documenten/rust2/src/libstd/panicking.rs:306:40
   |
306|             ptr::write(&mut (*data).r, f());
   |                                        ^^^
note: inside call to `std::panicking::try::do_call::<[closure@DefId(1/1:1801 ~ std[a0b6]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>`
  --> /home/bjorn/Documenten/rust2/src/libstd/panicking.rs:302:5
   |
302| /     fn do_call<F: FnOnce() -> R, R>(data: *mut u8) {
303| |         unsafe {
304| |             let data = data as *mut Data<F, R>;
305| |             let f = ptr::read(&mut (*data).f);
306| |             ptr::write(&mut (*data).r, f());
307| |         }
308| |     }
   | |_____^
note: inside call to `std::panicking::try::<i32, [closure@DefId(1/1:1801 ~ std[a0b6]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe]>`
  --> /home/bjorn/Documenten/rust2/src/libstd/panic.rs:361:9
   |
361|         panicking::try(f)
   |         ^^^^^^^^^^^^^^^^^
note: inside call to `std::panic::catch_unwind::<[closure@DefId(1/1:1801 ~ std[a0b6]::rt[0]::lang_start_internal[0]::{{closure}}[0]) 0:&&std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe], i32>`
  --> /home/bjorn/Documenten/rust2/src/libstd/rt.rs:58:25
   |
58 |           let exit_code = panic::catch_unwind(|| {
   |  _________________________^
59 | |             ::sys_common::backtrace::__rust_begin_short_backtrace(move || main())
60 | |         });
   | |__________^
note: inside call to `std::rt::lang_start_internal`
  --> /home/bjorn/Documenten/rust2/src/libstd/rt.rs:74:5
   |
74 |     lang_start_internal(&move || main().report(), argc, argv)
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0080`.

cc @oli-obk
blocking rust-lang/miri#364

[oli-obk]

0xFF is definitely missing some bytes. Do you have a dump that was run with RUST_LOG=rustc::mir::interpret?

[oli-obk]

I am working on this, just some bits that need cutting off.