Open Radar

 
Summary:
The published Swift grammar summary [1] has incorrect "for ... in" loop rules. Xcode doesn't compile programs that can be produced using the grammar. For example:

With the following productions:

for-in-statement → for ­pattern­ in ­expression ­code-block­
pattern → value-binding-pattern­
value-binding-pattern → var­ pattern­ | let ­pattern­

I can produce the following illegal programs (which Xcode rightly detects as illegal):

for var () in [] {}

The for-in loop doesn't accept a "value-binding-pattern".

On top, the "value-binding-pattern" shouldn't be recursive because that would make even less sense:

for var let var let var let () in [] {}

[1]: https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/zzSummaryOfTheGrammar.html