Type.Row

class RowLacking (entry :: Type) (key :: Symbol) (typ :: Type) (row :: Row Type) | entry typ -> key row

If you get "No type class instance was found" for this class, then your row shouldn't contain the label key.

Instances

• RowLacking entry key entry row

class RowLacks (key :: Symbol) (row :: Row Type) 

Encodes the constraint that a given row does not contain a specific key.