why is IReader using String instead of Text?

[marcosh]

IReader is defined as

type IReader t a = t -> Either String (a, t)

What is the reason why it is using String instead of Text for the failure case?

[Lysxia]

I would guess historical reasons, like that fail expects a String, or that libraries before text probably used String already for error messages.

There may be value in making Text really replace uses of String, but that transition seems like it should be decided and coordinated on a global level, starting with a strong enough motivation.