[project @ 2005-05-16 12:38:38 by simonpj]

Newtype representation

		Merge to STABLE

This commit fixes a long-standing bug (simple clerical error) in mkNewTyConRep,
which for some reason had gone un-discovered for years.

tc183 tests it.

diff --git a/ghc/compiler/iface/BuildTyCl.lhs b/ghc/compiler/iface/BuildTyCl.lhs
index 6636d77..44a8a76 100644 (file)
--- a/ghc/compiler/iface/BuildTyCl.lhs
+++ b/ghc/compiler/iface/BuildTyCl.lhs
@@ -80,6 +80,7 @@ mkNewTyConRhs tycon con
 mkNewTyConRep :: TyCon         -- The original type constructor
              -> Type           -- Chosen representation type
                                -- (guaranteed not to be another newtype)
+                               -- Free vars of rep = tyConTyVars tc
 
 -- Find the representation type for this newtype TyCon
 -- Remember that the representation type is the *ultimate* representation
@@ -103,11 +104,12 @@ mkNewTyConRep tc
        | tc `elem` tcs = unitTy
        | otherwise
        = case splitTyConApp_maybe rhs_ty of
-           Just (tc', tys) | isNewTyCon tc'
-                          -> substTyWith tc_tvs tys (go (tc:tcs) tc')
+           Just (tc1, tys) | isNewTyCon tc1
+                          -> ASSERT( length (tyConTyVars tc1) == length tys )
+                             substTyWith (tyConTyVars tc1) tys (go (tc:tcs) tc1)
            other          -> rhs_ty 
        where
-         (tc_tvs, rhs_ty) = newTyConRhs tc
+         (_tc_tvs, rhs_ty) = newTyConRhs tc
 
 
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