[mscharrer]

I ran into this issue once while trying to render the Mandelbrot set while learning Haskell. It defaulted to a rational type based on two bignum integers with unlimited precision.

With every Mandelbrot iteration* the integers doubled in size, producing exponential complexity. With 100 iterations this essentially means that the program never completes and even runs out of memory at some point.

The newbie-friendly feature turned out to be not so friendly.

* complex z_{n+1} = z_n^2 + c