[project @ 2000-02-28 09:17:54 by simonmar]

[ghc-hetmet.git] / ghc / compiler / types / TyCon.lhs

diff --git a/ghc/compiler/types/TyCon.lhs b/ghc/compiler/types/TyCon.lhs
index 28eaddf..14180b2 100644 (file)
--- a/ghc/compiler/types/TyCon.lhs
+++ b/ghc/compiler/types/TyCon.lhs
@@ -41,8 +41,11 @@ module TyCon(
 
 #include "HsVersions.h"
 
-import {-# SOURCE #-} Type  ( Type, Kind, SuperKind )
-import {-# SOURCE #-} DataCon ( DataCon )
+import {-# SOURCE #-} TypeRep ( Type, Kind, SuperKind )
+ -- Should just be Type(Type), but this fails due to bug present up to
+ -- and including 4.02 involving slurping of hi-boot files.  Bug is now fixed.
+
+import {-# SOURCE #-} DataCon ( DataCon, isExistentialDataCon )
 
 import Class           ( Class )
 import Var             ( TyVar )
@@ -273,10 +276,16 @@ isDataTyCon other = False
 isNewTyCon (AlgTyCon {algTyConFlavour = NewType}) = True 
 isNewTyCon other                                 = False
 
--- A "product" tycon is non-recursive and has one constructor, and is *not* an unboxed tuple
+-- A "product" tycon is 
+--     non-recursive 
+--     has one constructor, 
+--     is *not* existential
+--     is *not* an unboxed tuple
 -- whether DataType or NewType
-isProductTyCon (AlgTyCon {dataCons = [c], algTyConRec = NonRecursive}) = True
-isProductTyCon (TupleTyCon { tyConBoxed = boxed }) = boxed
+isProductTyCon (AlgTyCon {dataCons = [data_con], algTyConRec = NonRecursive}) 
+  = not (isExistentialDataCon data_con)
+isProductTyCon (TupleTyCon { tyConBoxed = boxed }) 
+  = boxed
 isProductTyCon other = False
 
 isSynTyCon (SynTyCon {}) = True