Non-exhaustive patterns in function zip_ty_env

The following code:

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

Produces this panic:

bug.hs:1:0:
    Data constructor `P' returns type `L2' instead of its parent type
    When checking the data constructor:ghc-6.4.1: panic! (the `impossible' happened, GHC version 6.4.1):
        types/Type.lhs:(1107,0)-(1108,77): Non-exhaustive patterns in function zip_ty_env

Trac metadata

Trac field	Value
Version	6.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information

Admin message

Non-exhaustive patterns in function zip_ty_env