Update rust toolchain version for Kani 0.24

[celinval]

Biweekly update for the rust toolchain version. For Kani 0.24, we will target the new year version: nightly-2023-03-09.

[celinval]

Please make sure you re-enable the rust compiler log that is being disabled in #2149

[celinval]

The related code is here:

kani/kani-compiler/src/session.rs

Lines 73 to 76 in 5195423

	// TODO: Enable rustc log when we upgrade the toolchain.
	// <https://github.com/model-checking/kani/issues/2283>
	//
	// rustc_driver::init_rustc_env_logger();

[qinheping]

@tautschnig
I tried to update toolchain to nightly-2023-03-09. I resolved all build error in #2293. However, there are still some compilation bugs. Here is the simplest way to reproduce the bug.

1. In the main brach, modify the toolchain to nightly-2023-02-05---the earliest toolchain with which I can reproduce the bug. And build Kani.
2. Run kani tests/kani/Arbitrary [arbitrary_structs.rs](http://arbitrary_structs.rs/)
3. Error message:

thread 'rustc' panicked at 'not implemented', kani-compiler/src/codegen_cprover_gotoc/codegen/rvalue.rs:318:50
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Kani unexpectedly panicked during compilation.
Please file an issue here: https://github.com/model-checking/kani/issues/new?labels=bug&template=bug_report.md

[Kani] current codegen item: codegen_function: std::ptr::from_raw_parts_mut::<[std::mem::MaybeUninit<PercentArbitrary>]>
_RINvNtNtCs7cJSzKcgVKk_4core3ptr8metadata18from_raw_parts_mutSINtNtNtB6_3mem12maybe_uninit11MaybeUninitNtCsaStLaCc7KW0_17arbitrary_structs16PercentArbitraryEEB1E_
[Kani] current codegen location: Loc { file: "/Users/qinhh/.rustup/toolchains/nightly-2023-02-05-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/ptr/metadata.rs", function: None, start_line: 128, start_col: Some(1), end_line: 131, end_col: Some(12) }
error: /Users/qinhh/Repos/kani/qinheping/target/kani/bin/kani-compiler exited with status exit status: 101

I asked Celina about this bug, and here is what she found

it looks like the compiler changed how they deal with deaggregation rust-lang/rust#107267
so we will need to implement the rvalue aggregation for structs / unions

[zhassan-aws]

For the record, this commit has the changes to the cranelift backend to handle the changes in rust-lang/rust#107267:

bjorn3/rustc_codegen_cranelift@8494882

It may give us a hint of the changes needed on the Kani side.

[tautschnig]

If I understand https://doc.rust-lang.org/beta/nightly-rustc/rustc_middle/mir/enum.AggregateKind.html#variant.Adt correctly, we need to generate struct or union expressions here while asserting that VariantIdx always be zero. GOTO has these, so generating shouldn't be very hard once it is clear where to obtain the type information and all the operands.

Edit: this is about https://github.com/model-checking/kani/blob/main/kani-compiler/src/codegen_cprover_gotoc/codegen/rvalue.rs#L318; for struct expressions it should be the same code as the Tuple case handled in the lines just before.

[celinval]

Unfortunately we were not able to do the update on time. We have now switched it to a tentative nightly update.