[kibwen]

  > The cascade of efforts at error handling

You must be referring to ancient Rust with its condition system and such. Modern Rust code just uses Result types.

  > rather than getting on with higher-kinded types to allow 
  > them to do it right

Er, no, you don't need HKTs to "do it right", you'd just need HKTs to do it generically. Rust's error handling works fine for specific types; you can even write macros to emulate do-notation (and people have).

  > Allowing "return"

Welcome to the realities of imperative programming. :) Unlike Scala, Rust does not aspire to functional godhood.

  > Mandating braces for functions and control flow constructs

Scope in Rust is very, very important for expressing when references go out of scope and when resources are freed. Leaving scope implicit would be massively frustrating.

  > the scala/ruby style of passing a closure

Rust had internal iterators for years, and the entire `for` construct was based around them. They were removed because they were found wanting.

As I've mentioned in a sibling comment, the lessons that Scala may have learned in its life do not necessarily apply to Rust. They are very, very different languages.

[drewhk]

I am a Scala developer but I agree with your points. The only thing that just simply drives me mad in Rust is mandatory semicolons. Once you are used to be able to omit them then it gets really annoying to go back using them.

[kibwen]

I actually agree with this one. :) The usual argument in their favor is that having to explicitly return `()` all the time would get tired in low-level C-alike functions that mostly operate via side effects, but I'm not particularly swayed that we should be optimizing for that use case (but then again I'm also of the opinion that bitwise operators don't deserve their own symbols, so I may already be an enemy of this crowd :P ).