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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 12 Jul 2020 13:33:57 -0700
Message-ID: <CAHk-=wi=xTmhnL4go0v5BaYRz_81kranLvniA5X8_zq_uCkaOA@mail.gmail.com>
Subject: Re: Linux kernel in-tree Rust support
To:     Josh Triplett <josh@joshtriplett.org>
Cc:     Adrian Bunk <bunk@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        alex.gaynor@gmail.com, geofft@ldpreload.com, jbaublitz@redhat.com,
        Masahiro Yamada <masahiroy@kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Sun, Jul 12, 2020 at 12:39 PM Josh Triplett <josh@joshtriplett.org> wrote:
>
> Rust has hard stability guarantees when upgrading from one stable
> version to the next.

I think the worry is more about actual compiler bugs, not the set of
exposed features.

That's always been the biggest pain point. Compiler bugs are very
rare, but they are so incredibly hard to debug when they happen that
they end up being extra special.

Random "we need this compiler for this feature" is actually fairly
rare. Yes, the most recent case of me just saying "let's use 4.9
rather than 4.8" was due to that, but honestly, that's the exception
rather than the rule, and is to occasionally simplify the code (and
the test coverage).

The most common case of compiler version checks are due to "compiler
XYZ is known to mis-compile ABC on target IDK".

                    Linus