Understanding the different behavior of thunks when GHCi let bindings are involved

Question

I\'ve been playing with some examples from Simon Marlow\'s book about parallel and concurrent programming in Haskell and stumbled across an interesting behavior that I don\'t re

Answer 1

Because (,) is a constructor, the difference makes no difference to Haskell's semantics (:sprint gives access to internal thunk implementation details so doesn't count.) So this is a question of which optimizations and trade-offs GHC does when compiling (x,x) in different positions. Someone else may know the precise reason in these cases.