That would be helpful, but the problem is not so much that you don't know when an optimisation will happen but that its often a fragile condition. Seemingly tri

That would be helpful, but the problem is not so much that you don't know when an optimisation will happen but that its often a fragile condition. Seemingly trivial changes can wreak havoc on your performance. When using GHC I often end up with code that I just can't change without turning a 1MB process into a swap eating monster. The best thing about haskell is that encourages really clear, high-level code. Having to tiptoe around hard-to-predict performance bombs is definitely against the spirit of declarative code.