X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=ghc%2Fcompiler%2Fprelude%2FPrelVals.lhs;h=84fd4d915a3ac42a5509114880c7fd0e21f4c3ed;hp=37d6f6b746c8d0b4b46825016b884fc28e8b9cf6;hb=5eb1c77c795f92ed0f4c8023847e9d4be1a4fd0d;hpb=f7ecf7234c224489be8a5e63fced903b655d92ee

diff --git a/ghc/compiler/prelude/PrelVals.lhs b/ghc/compiler/prelude/PrelVals.lhs
index 37d6f6b..84fd4d9 100644
--- a/ghc/compiler/prelude/PrelVals.lhs
+++ b/ghc/compiler/prelude/PrelVals.lhs
@@ -109,6 +109,9 @@ openAlphaTy = mkTyVarTy openAlphaTyVar
 
 errorTy  :: Type
 errorTy  = mkSigmaTy [openAlphaTyVar] [] (mkFunTys [mkListTy charTy] openAlphaTy)
+    -- Notice the openAlphaTyVar.  It says that "error" can be applied
+    -- to unboxed as well as boxed types.  This is OK because it never
+    -- returns, so the return type is irrelevant.
 \end{code}
 
 We want \tr{GHCbase.trace} to be wired in