6.4.1: "Non-exhaustive patterns in function zip_ty_env"

[Kimberley Burchett]

When I load the following erroneous code into ghci:

> data T a where
>     P :: L1 -> L2
> data L1 = L1
> data L2 = L2

... I get this error:

bug.hs:7:0:
     Data constructor `P' returns type `L2' instead of its parent type
     When checking the data constructor:*** Exception: 
types/Type.lhs:(1107,0)-(1108,77): Non-exhaustive patterns in function 
zip_ty_env

I'm using ghc 6.4.1, on FC4/i386.

Kimberley Burchett
http://www.kimbly.com/