Purity problems in Rust

[Dicebot]

On Thursday, 19 December 2013 at 22:07:31 UTC, bearophile wrote:
> Why they have removed (?) purity-on-default from Rust language:
> http://article.gmane.org/gmane.comp.lang.rust.devel/3855
>
>
> There is also the Reddit thread:
> http://www.reddit.com/r/programming/comments/1t8y6g/why_rust_ditched_pure_functions/
>
> Bye,
> bearophile

Have just read that and my reaction was "woot?" (though as far as 
I have understood, it is not being removed, just refused to be 
added). Well decision itself is discussable but rationale comes 
essentially to "we can't define what `pure` means" which is.. 
weird.