-pprUserTypeCtxt (FunSigCtxt n) = ptext SLIT("the type signature for") <+> quotes (ppr n)
-pprUserTypeCtxt ExprSigCtxt = ptext SLIT("an expression type signature")
-pprUserTypeCtxt (ConArgCtxt c) = ptext SLIT("the type of the constructor") <+> quotes (ppr c)
-pprUserTypeCtxt (TySynCtxt c) = ptext SLIT("the RHS of the type synonym") <+> quotes (ppr c)
-pprUserTypeCtxt GenPatCtxt = ptext SLIT("the type pattern of a generic definition")
-pprUserTypeCtxt LamPatSigCtxt = ptext SLIT("a pattern type signature")
-pprUserTypeCtxt BindPatSigCtxt = ptext SLIT("a pattern type signature")
-pprUserTypeCtxt ResSigCtxt = ptext SLIT("a result type signature")
-pprUserTypeCtxt (ForSigCtxt n) = ptext SLIT("the foreign declaration for") <+> quotes (ppr n)
-pprUserTypeCtxt DefaultDeclCtxt = ptext SLIT("a type in a `default' declaration")
-pprUserTypeCtxt SpecInstCtxt = ptext SLIT("a SPECIALISE instance pragma")
-
-
---------------------------------
-tidySkolemTyVar :: TidyEnv -> TcTyVar -> (TidyEnv, TcTyVar)
--- Tidy the type inside a GenSkol, preparatory to printing it
-tidySkolemTyVar env tv
- = ASSERT( isSkolemTyVar tv || isSigTyVar tv )
- (env1, mkTcTyVar (tyVarName tv) (tyVarKind tv) info1)
+pprUserTypeCtxt (FunSigCtxt n) = ptext (sLit "the type signature for") <+> quotes (ppr n)
+pprUserTypeCtxt ExprSigCtxt = ptext (sLit "an expression type signature")
+pprUserTypeCtxt (ConArgCtxt c) = ptext (sLit "the type of the constructor") <+> quotes (ppr c)
+pprUserTypeCtxt (TySynCtxt c) = ptext (sLit "the RHS of the type synonym") <+> quotes (ppr c)
+pprUserTypeCtxt GenPatCtxt = ptext (sLit "the type pattern of a generic definition")
+pprUserTypeCtxt ThBrackCtxt = ptext (sLit "a Template Haskell quotation [t|...|]")
+pprUserTypeCtxt LamPatSigCtxt = ptext (sLit "a pattern type signature")
+pprUserTypeCtxt BindPatSigCtxt = ptext (sLit "a pattern type signature")
+pprUserTypeCtxt ResSigCtxt = ptext (sLit "a result type signature")
+pprUserTypeCtxt (ForSigCtxt n) = ptext (sLit "the foreign declaration for") <+> quotes (ppr n)
+pprUserTypeCtxt DefaultDeclCtxt = ptext (sLit "a type in a `default' declaration")
+pprUserTypeCtxt SpecInstCtxt = ptext (sLit "a SPECIALISE instance pragma")
+pprUserTypeCtxt GenSigCtxt = ptext (sLit "a type expected by the context")
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{TidyType}
+%* *
+%************************************************************************
+
+\begin{code}
+-- | This tidies up a type for printing in an error message, or in
+-- an interface file.
+--
+-- It doesn't change the uniques at all, just the print names.
+tidyTyVarBndr :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
+tidyTyVarBndr env@(tidy_env, subst) tyvar
+ = case tidyOccName tidy_env occ1 of
+ (tidy', occ') -> ((tidy', subst'), tyvar'')
+ where
+ subst' = extendVarEnv subst tyvar tyvar''
+ tyvar' = setTyVarName tyvar name'
+
+ name' = tidyNameOcc name occ'
+
+ -- Don't forget to tidy the kind for coercions!
+ tyvar'' | isCoVar tyvar = setTyVarKind tyvar' kind'
+ | otherwise = tyvar'
+ kind' = tidyType env (tyVarKind tyvar)
+ where
+ name = tyVarName tyvar
+ occ = getOccName name
+ -- System Names are for unification variables;
+ -- when we tidy them we give them a trailing "0" (or 1 etc)
+ -- so that they don't take precedence for the un-modified name
+ occ1 | isSystemName name = mkTyVarOcc (occNameString occ ++ "0")
+ | otherwise = occ
+
+
+---------------
+tidyFreeTyVars :: TidyEnv -> TyVarSet -> TidyEnv
+-- ^ Add the free 'TyVar's to the env in tidy form,
+-- so that we can tidy the type they are free in
+tidyFreeTyVars env tyvars = fst (tidyOpenTyVars env (varSetElems tyvars))
+
+---------------
+tidyOpenTyVars :: TidyEnv -> [TyVar] -> (TidyEnv, [TyVar])
+tidyOpenTyVars env tyvars = mapAccumL tidyOpenTyVar env tyvars
+
+---------------
+tidyOpenTyVar :: TidyEnv -> TyVar -> (TidyEnv, TyVar)
+-- ^ Treat a new 'TyVar' as a binder, and give it a fresh tidy name
+-- using the environment if one has not already been allocated. See
+-- also 'tidyTyVarBndr'
+tidyOpenTyVar env@(_, subst) tyvar
+ = case lookupVarEnv subst tyvar of
+ Just tyvar' -> (env, tyvar') -- Already substituted
+ Nothing -> tidyTyVarBndr env tyvar -- Treat it as a binder
+
+---------------
+tidyType :: TidyEnv -> Type -> Type
+tidyType env@(_, subst) ty
+ = go ty