// 1
something?.let { return it }

Or

// 2
if(something != null) { return something }

If

something

is mutable and accessible from other threads,

2

might still return null

won't smart-cast not be available in that case?

Smart cast to 'Int' is impossible, because 'something' is a mutable property that could have been changed by this time

(assuming

something

is an Int?) (so the compiler actually stops you from making this mistake)

IMO I like the option 2 for being simpler for people that aren't kotlin developers. 99.999997% (made up stats) programming languages have a if statement.

My commentary would be to refrain from multiple/short-circuiting returns. For me this would be prime example to use if as an expression: return

if (something == null) calculateAlternative() else something

Or even

return something ?: calculateAlternative()

Lovely usage of the elvis operator.

also for short expressions you can remove curly praces and option 2 becomes even shorter and more clean:

if (something != null) return something