1.54.0 compilation fault with nightly, miri and parallel-compiler

[Miezhiko]

error[E0308]: mismatched types
  --> src/tools/miri/src/bin/miri.rs:44:30
   |
44 |                 Rc::make_mut(&mut crate_source).rlib = Some((PathBuf::new(), PathKind::All));
   |                              ^^^^^^^^^^^^^^^^^ expected struct `Rc`, found struct `Arc`
   |
   = note: expected mutable reference `&mut Rc<_>`
              found mutable reference `&mut Arc<CrateSource>`

error[E0609]: no field `rlib` on type `&mut _`
  --> src/tools/miri/src/bin/miri.rs:44:49
   |
44 |                 Rc::make_mut(&mut crate_source).rlib = Some((PathBuf::new(), PathKind::All));
   |                                                 ^^^^

[Urgau]

Miri is a nightly-only tool, not a stable one. You shouldn't being able to built it from a stable release.
See #86436 for more informations.

[Miezhiko]

I use nightly flag too, I'm just using release sources.

[Urgau]

The release source shouldn't include miri, in fact I don't see it in the release source. Where did you download it ? Have you used the official tarballs ?

Miri is also one of the few tools that are allow to not always compile, see the Rustup Components History. So it's perfectly possible that when the beta-cut happen miri was not compiling at the moment.

[Miezhiko]

miri can be set as additional tool in tools in config.toml before build, it needs nightly flag too (I have it), yes I use official tarballs, I wonder if there is patch for it already, maybe this issue should be on miri repository.

[ghost]

   = note: expected mutable reference `&mut Rc<_>`
             found mutable reference `&mut Arc<CrateSource>`

That looks like a parallel_compiler issue rather than a toolstate issue.

[Miezhiko]

   = note: expected mutable reference `&mut Rc<_>`
             found mutable reference `&mut Arc<CrateSource>`

That looks like a parallel_compiler issue rather than a toolstate issue.

Okay, what is parallel_compiler? Is it related with parallel compilation (many jobs) or is it some crate?

[Miezhiko]

Sub-module hashtag for 1.54.0 tag is the same as for master at the moment https://github.com/rust-lang/rust/tree/1.54.0/src/tools

[ghost]

Okay, what is parallel_compiler? Does it related with parallel rust compilation (many jobs) or is it some crate?

rust/config.toml.example

Lines 457 to 459 in 1195bea

	# Build a multi-threaded rustc
	# FIXME(#75760): Some UI tests fail when this option is enabled.
	#parallel-compiler = false

[Miezhiko]

@hyd-dev yes I have it enabled too

[Urgau]

miri can be set as additional tool in tools in config.toml before build, it needs nightly flag too (I have it), yes I use official tarballs, I wonder if there is patch for it already, maybe this issue should be on miri repository.

Yes, but as I said before miri as no guarantee to build with any rust version or even master.
Because 1.54.0 was cut many weeks ago, the problem has already be fixed on master.

Sub-module hashtag for 1.54.0 tag is the same as for master at the moment https://github.com/rust-lang/rust/tree/1.54.0/src/tools

I don't know were you are looking, but it's not the case, the 1.54.0 beta-cut happen 6 weeks ago. There have been many commit since.

[ghost]

the problem has already be fixed on master

I don't think Miri on master works with parallel-compiler = true. The code still uses Rc which would not be work with parallel-compiler = true:
https://github.com/rust-lang/miri/blob/453e3ef7dab5aad6450bee09b2c02de94c5b18cb/src/bin/miri.rs#L45.
I don't know whether Miri is intended to work with parallel-compiler = true or not, at least it's not tested in CI.

[Miezhiko]

@hyd-dev it was working for me on 1.53.0

[Urgau]

Maybe @RalfJung (the miri maintainer) can help you here.

[Mark-Simulacrum]

parallel-compiler = true is not a supported configuration at this time, both for rustc and especially for tools. I'd expect that patches to fix compilation and runtime bugs to be accepted for the most part, but there's not currently active development on that configuration and it's definitely not expected that git tags (i.e., stable releases) will build with parallel compiler enabled.

[RalfJung]

Shouldn't #86413 have landed the change that avoids Miri being built on stable? Or do we need some other change so it is not in tools by default?

[RalfJung]

@Miezhiko why did you even build Miri? Did you explicitly ask for it in your config.toml, or did it get enabled implicitly somehow?

(If you want to build Miri, you should always use a nightly compiler. That is the only configuration we support. And even then, not all nightlies come with Miri, see https://rust-lang.github.io/rustup-components-history/. Sometimes stable releases don't come with a working Miri at all; sometimes it just happens to work, but that's basically a 'happy accident'.)

[Miezhiko]

@RalfJung I enable it manually in config.toml (was thinking maybe it may be useful for me in future) I also build with nightly flag, needed for some features (not sure if FFI is stable already), I'm closing this but personally I'd port (if I know which one) patch fixing this error into sources from which ones I rebuild rust.

[RalfJung]

I also build with nightly flag

Yeah, that doesn't really help for nightly tools like Miri.
The nightly flag will get you a rustc that can use feature, but we're still not making any promises about the Miri in a stable release even building.

That said, if you are okay with patching things, I'm happy to give pointers for which patches you'll likely need. :)