[dparoski]

Engineer working on Hack here.

You can actually write you example a bit more concisely in Hack: "$y ==> $y + 1".

[iso8859-1]

Return statements are optional? So it's just the last statement in a function that'll get returned?

[dparoski]

The "return" keyword is not needed if the right hand side of the lambda arrow ("==>") is an expression that is not wrapped in curly braces.

If the right hand side _is_ wrapped in curly braces then it is treated as a list of statements, in which case you do need to use the "return" keyword.

[dparoski]

Edit: My previous comment was referring to the second occurrence of "return" in your example (after the "==>" arrow). Just noticed I mistakenly dropped the first occurrence of "return"; the first occurrence of "return" in your example is needed.