Basically just learning haskell, I would have posted this in the beginners list but since it involves a segfault of GHCI, I figured it might be worth posting here. I was trying to get a good understanding of local variable scoping issues, so I tried the following: f :: (Num a) => a -> a f x = let p = x*x in let p = x*p in p I have some background in ML, which led me to believe that what should happen here is that the function would return x^3. Instead, GHCI just completely terminates, I guess with a segfault. What's the "correct" behavior here? Should it even compile? I understand that you can't redefine the same symbol twice in the same scope, so I tried this specifically to see what would happen if you defined the same variable again in a nested scope. I thought it would just shadow the original declaration, while still using the original p to calculate the value of the new p. I don't think the problem is the re-declaration of the same symbol in a nested scope (although if someone could clarify that would be nice), but rather the fact that I've attempted to use the previous declaration of p in defining the new declaration of p. Would it be a safe assumption that a bug report should be submitted over this?