FIX Trac #1806: test for correct arity for datacon in infix pattern patch

[ghc-hetmet.git] / compiler / typecheck / TcDeriv.lhs

diff --git a/compiler/typecheck/TcDeriv.lhs b/compiler/typecheck/TcDeriv.lhs
index bbdd9b2..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.
 

@@ -654,7 +657,7 @@ cond_mayDeriveDataTypeable (mayDeriveDataTypeable, _)
  | mayDeriveDataTypeable = Nothing
  | otherwise = Just why
   where
  | mayDeriveDataTypeable = Nothing
  | otherwise = Just why
   where

-    why  = ptext SLIT("You need -fglasgow-exts to derive an instance for this class")
+    why  = ptext SLIT("You need -XDeriveDataTypeable to derive an instance for this class")

 
 std_class_via_iso :: Class -> Bool
 std_class_via_iso clas -- These standard classes can be derived for a newtype
 
 std_class_via_iso :: Class -> Bool
 std_class_via_iso clas -- These standard classes can be derived for a newtype