On Wed, Apr 2, 2014 at 9:51 AM, Edward Kmett <ekmett@gmail.com> wrote:
This is where the data type contexts came from. They were originally motivated by the needs of the no-longer existent Seq class, and then subverted to make Complex less useful than it otherwise could be. ;)

This is wrong. Data type contexts existed in the Haskell 1.0 report, and Ratio and Complex used them there. Strict fields didn't exist until 1.3.

-- Dan