I have mixed feelings on this. On one hand I did want this notation while learning haskell. Partly because there are a bunch of places in haskell's type system

I have mixed feelings on this. On one hand I did want this notation while learning haskell. Partly because there are a bunch of places in haskell's type system where repeating a variable implicitly gives equality constraints. On the other hand something like drop _ [] = [] drop x (y:xs) | x == y = drop x xs | otherwise = y : drop x xs is often more readable at a glance to me since I don't have to parse variable names to see control flow structures. Also, in statically typed languages what happens if equality doesn't work for a value.