From 2140e8a5ce58bc619cdbeea0fb93b07779964b4f Mon Sep 17 00:00:00 2001
From: Simon Peyton Jones <simonpj@microsoft.com>
Date: Thu, 10 Oct 2013 10:53:41 +0100
Subject: Comments only

---
 compiler/typecheck/TcInstDcls.lhs | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'compiler')

diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs
index 381c0823cc..6d4e620534 100644
--- a/compiler/typecheck/TcInstDcls.lhs
+++ b/compiler/typecheck/TcInstDcls.lhs
@@ -1358,6 +1358,9 @@ tcInstanceMethods dfun_id clas tyvars dfun_ev_vars inst_tys
 -- Notice that the dictionary bindings "..d1..d2.." must be generated
 -- by the constraint solver, since the <context> may be
 -- user-specified.
+--
+-- See also Note [Newtype deriving superclasses] in TcDeriv
+-- for why we don't just coerce the superclass
 
   = do { rep_d_stuff <- checkConstraints InstSkol tyvars dfun_ev_vars $
                         emitWanted ScOrigin rep_pred
-- 
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