Unfortunately rustc uses rust features almost immediately (I think even features introduced in the immediately preceding version?), so you get a bootstrap chain, and if you start with the compiler written in OCaml you now need to build every single rustc version ever released.

This takes very long and is error-prone, so having a compiler that can build even an intermediate version is already a big help.

See e.g. https://guix.gnu.org/blog/2018/bootstrapping-rust/

It's unfortunate that Rust has adopted development policies that are so hostile towards bootstrapping and cross-compiling rustc. The fact that most of the people cheerleading for Rust the ecosystem don't even see this as a problem is enough to convince me to steer clear of anything involving Rust the language.

You don't have a real language until there is a stable specification and multiple independent implementations. Until then it's just an experimental toy.

>is enough to convince me to steer clear of anything involving Rust the language.

This has a "I will cancel my subscription" letters to the editor feel, as if anyone cares :-)

I mean, there are pros and cons to any language and ecosystem. "I found some fault in bootstrapping approach and will condemn the whole language/effort for it" is a hardly a reasonable argument...

As if regular devs often have a need to bootstrap from scratch themselves...

You can't build GCC on MSVC or vis versa.

And people do see the pain here as a problem, that's why the project in this very thread exists. I think most in the Rust community see mrustc and the pressure that an independent implementation brings process wise as a very good thing for the language.

At least some years ago, you could build GCC on MSVC just fine. (Did it for GCC 3.3 and 4.2 on Interix way back then)

It should probably be still functional, or easily fixed if not.

Ah yes! The experimental toy languages without specification like Python.

CPython is the only viable Python interpreter, and the Python language specification is "whatever CPython does". In my humble opinion this disqualifies Python from consideration as a language.

That doesn't mean Python isn't useful! It is in fact a wildly successful tool that has spawned a large ecosystem of packages and a diverse group of users. But it unfortunately does not qualify as a true language, for it lacks the necessary ingredients: a formal specification of the language and more than one implementation of said specification.

I'm sorry, what are PEPs, again?

PEPs are specification fragments. But it's far from a complete python language specification.

Since then they've bootstrapped their way from 1.28 all the way to 1.50: https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages...

Of course, but AFAIU this massively shortens the chain. Newer versions of rustc up the minimum compiler version required for building all the time.