I've gotten into a habit of preceding most "do"s in my code with a "$", and indenting the next line. I kind of like this, since it makes the indentation more uniform. But it seems to have bitten me now. I'd like to write something like this s = sum $ do x <- [1,2,3] let b = sum $ do y <- [0..x + 1] return y return (x + b) But GHC complains of "Empty 'do' construct". It likes the alternative s' = sum $ do x <- [1,2,3] let b = sum $ do y <- [0..x + 1] return y return (x + b) just fine, but that looks horrible to me (ok, "horrible" is a bit strong, but I don't like it as much). So I'm wondering, (1) Is this intended to give an error, or is it just a momentary hiccup, and (2) if others have run into this, is there a more aesthetic alternative that works? Thanks, Chad