Comment re Trac #1220

diff --git a/compiler/typecheck/TcDeriv.lhs b/compiler/typecheck/TcDeriv.lhs
index d414c6f..774bbe9 100644 (file)
--- a/compiler/typecheck/TcDeriv.lhs
+++ b/compiler/typecheck/TcDeriv.lhs
@@ -222,6 +222,9 @@ And then translate it to:
        
 Note [Newtype deriving superclasses]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        
 Note [Newtype deriving superclasses]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

+(See also Trac #1220 for an interesting exchange on newtype
+deriving and superclasses.)
+

 The 'tys' here come from the partial application in the deriving
 clause. The last arg is the new instance type.
 
 The 'tys' here come from the partial application in the deriving
 clause. The last arg is the new instance type.