So I've been excising occurrences of the [n..m] syntax from my code. The reason is that I had been using [0..5] as a shorthand for [0, 1, 2, 3, 4, 5], mostly in tests. This works for integral types and it appears to work for floating point types. Then I tried switching to a fixed point format, and discovered my mistake. Enum is supposed to enumerate every value between the two points, and the result is memory exhaustion. I had already been switching from enumFrom because they accumulate floating point errors, in favor of a couple of more appropriate functions: -- | Enumerate an inclusive range. Uses multiplication instead of successive -- addition to avoid loss of precision. -- -- Also it doesn't require an Enum instance. range :: (Num a, Ord a) => a -> a -> a -> [a] range start end step = go 0 where go i | val > end = [] | otherwise = val : go (i+1) where val = start + (i*step) -- | Like 'range', but includes the end. range_end :: (Num a, Ord a) => a -> a -> a -> [a] range_end start end step = go 0 where go i | val >= end = [end] | otherwise = val : go (i+1) where val = start + (i*step) -- | Infinite range. range_ :: (Num a) => a -> a -> [a] range_ start step = go 0 where go i = start + (i*step) : go (i+1) So I think the Enum instances for Float and Double are sort of a trap. They misled me into thinking the .. syntax is the range function defaulting to a step of 1, led to precision errors I had to debug then fix (and I've noticed lead to the odd stack overflow question), then led to more disaster when I switched to an Enum instance that lived up to Enum's real purpose. The problem is that the [..] syntax is convenient and tempting, especially for tests, wanting a numeric range (rather than enumeration) is very common, and as far as I know the 'range' function isn't in the standard library. So it seems like one of these things that seem convenient in the short term but come around and bite you later. Using the right functions from the start avoids all that. Is there any support for the idea of removing Enum instances for floating point numbers?