(It may be the case that these things absolutely cannot be handled in a systematic way in a no-GC/no-runtime language, but I'd really like to see some evidence that this is the case.)
I can only think of one redundant feature, and that is the ? operator. This is because `try!` gets used very often in in a lot of code.
I can only think of one syntactic feature (redundant or otherwise) that doesn't get used often and that is HRTB(`for<'a>`), which needs to be there to be able to specify some types correctly (but is very rare).
By special-casing now, one almost-certainly[1] closes the opportunity for future consolidation.
[1] I say almost because it's not necessarily a done deal, but migration gets exponentially harder the longer a language has been "out in the wild". GHC/Haskell has gone through a similar upheaval in the last 1-2 years and it wasn't pretty... but ultimately it seems to at least have survived, so there's that.
Rust will certainly have warts. Maybe someday in the future we'll feel like this is one of them, maybe not. :)
True, and I think I acknowledged as much in my original comment.
> And people need to reduce their error-handling boilerplate today.
Indeed, I'm just (vaguely) worried about Rust being painted into a corner. As I said in my OP, it may actually be an unavoidable corner -- I hope not, but as you say... I guess we'll see :).
>
> closes the opportunity
The door isn't closed for this, `?` works with a "carrier" trait, which lets you extend the operator. Now, it's currently unstable, so right now you can't use it, but the door is wide open for the design of `Carrier` to be finalized.
This was explicitly discussed and thought out before ? was stabilized. It's just that ? was stabilized before Carrier.
The compiler knows nothing about `Result`. There are very few structs that it knows anything about, and these all have to do with atomics or `UnsafeCell` or other intrinsic-based primitives that you don't need to reimplement out-of-tree anyway. It knows a few traits, like Add and Copy and Carrier, which can be used to extend operators and stuff.
Oh, OK that at least sound like sound "defensive design" -- good to hear :). However, what happens if `Carrier` needs to be radically redesigned, e.g. to account for HKTs or Rank-N types (or something similarly 'crazy').
In this sense, ? is following in a long tradition.
https://en.wikipedia.org/wiki/Safe_navigation_operator
To the contrary of what you're suggesting, I think Rust has done a great job eliminating a lot of the previous special-cased syntax and rebuilding things upon a simplified set of core primitives.
What worries you about it? What things need to be "handled in a systematic way"? Are you just generally opposed to any new syntax in languages or something?