Remove unchecked_shr/shl from intrinsics

[TimDiekmann]

r? @RalfJung

This PR adds a check in the intrinsics itself. It's not needed anymore.

[RalfJung]

rust-lang/rust#53697 also implemented some other intrinsics, could you remove those as well?

[TimDiekmann]

Do I assume correctly when rust-lang/rust#53991 was merged and landed on the latest nightly, the tests will pass?

[RalfJung]

Thanks!

Do I assume correctly when rust-lang/rust#53991 was merged and landed on the latest nightly, the tests will pass?

Basically, yes -- except you will also have to update the rust-toolchain file in this repo to specify said nightly.

[TimDiekmann]

Basically, yes -- except you will also have to update the `rust-toolchain` file in this repo to specify said nightly.

I may change this when the new nightly lands.

[TimDiekmann]

rust-lang/rust#53991 was merged, however with nightly-2018-09-08 it fails to compile:

error[E0277]: the trait bound `for<'a> MemoryData<'_>: rustc_data_structures::stable_hasher::HashStable<rustc::ich::StableHashingContext<'a>>` is not satisfied
   --> src/lib.rs:281:18
    |
281 | impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
    |                  ^^^^^^^^^^^^^^^^^^^ the trait `for<'a> rustc_data_structures::stable_hasher::HashStable<rustc::ich::StableHashingContext<'a>>` is not implemented for `MemoryData<'_>`

[RalfJung]

Ah, that looks like a fall-out from rust-lang/rust#52626... however, memory is not being hashed any more, so we should likely remove the trait bounds at https://github.com/rust-lang/rust/blob/dac76020a5a33fa723d578043e422455e598620b/src/librustc_mir/interpret/machine.rs#L30 and https://github.com/rust-lang/rust/blob/dac76020a5a33fa723d578043e422455e598620b/src/librustc_mir/interpret/machine.rs#L33.

But that still leaves the bound on the Machine itself. miri will need to do something like https://github.com/rust-lang/rust/blob/dac76020a5a33fa723d578043e422455e598620b/src/librustc_mir/interpret/eval_context.rs#L186. Do you want to give that a try? Otherwise I'll do it in a week or so, when I am back from my vacation.

[RalfJung]

Actually never mind -- miri shouldn't have any Hash or StableHash implementation. So once rust-lang/rust#54076 lands, you should be good.

[RalfJung]

I pushed a commit to this PR that makes miri compile again once rust-lang/rust#54076 lands.