| {-# INLINE foo #-} | foo = large | | bar x = if x then res else res | where res = foo | | By putting an INLINE on foo I am able to persuade it to be inlined | into the binding of bar, but I can't then persuade it to be inlined at | the let expression. I'm not certain what you mean here. I think you mean that in the above code you end up with bar x = let res = large in if x then res else res whereas what you wanted was bar x = if x then large else large That is indeed tricky in general, as I'm sure you can see: let x = <large> in let y = e2[x,x] in let z = e3[y] in ... Is it better to inline x into e2, or y into e3, or z into e4? Hard to tell! In your example, you want 'res' to inline "first". You can get that by explicit control: {-# NOINLINE [0] foo #-} That says "don't inline foo before phase 0", which in turn gives time for 'res' to get inlined first. I'm not certain whether that'll help in your actual example. Simon