Simon Peyton-Jones wrote:
| The source code has explicit monomorphic types all over it; I would | expect GHC to be able to optimise out any method calls. (OTOH, I'm not a | GHC expert... Simon? Don?)
Full monomorphisation is a whole-program optimisation and GHC isn't (yet) a whole-program compiler. Overloaded functions are indeed specialised for the types at which they are called *in the module they are defined*.
Simon
What I'm trying to say is, I would have expected, say, resultant :: [Vector2] -> Vector2 resultant = sum to run faster than resultant = sum In the latter case, we have resultant :: (Num n) => [n] -> n. I'm no expert, but I would expect that this requires a method lookup on each call, whereas with the more restrictive type I would expect the compiler to be able to just link directly to the correct method implementation. Am I mistaken?