+ Meta type variable bindings
+%* *
+%************************************************************************
+
+\begin{code}
+getTcTyVarBindsVar :: TcM (TcRef TcTyVarBinds)
+getTcTyVarBindsVar = do { env <- getLclEnv; return (tcl_tybinds env) }
+
+getTcTyVarBinds :: TcM a -> TcM (a, TcTyVarBinds)
+getTcTyVarBinds thing_inside
+ = do { tybinds_var <- newMutVar emptyBag
+ ; res <- updLclEnv (\ env -> env { tcl_tybinds = tybinds_var })
+ thing_inside
+ ; tybinds <- readMutVar tybinds_var
+ ; return (res, tybinds)
+ }
+
+bindMetaTyVar :: TcTyVar -> TcType -> TcM ()
+bindMetaTyVar tv ty
+ = do { ASSERTM2( do { details <- readMutVar (metaTvRef tv)
+ ; return (isFlexi details) }, ppr tv )
+ ; tybinds_var <- getTcTyVarBindsVar
+ ; tybinds <- readMutVar tybinds_var
+ ; writeMutVar tybinds_var (tybinds `snocBag` TcTyVarBind tv ty)
+ }
+
+getTcTyVarBindsRelation :: TcM [(TcTyVar, TcTyVarSet)]
+getTcTyVarBindsRelation
+ = do { tybinds_var <- getTcTyVarBindsVar
+ ; tybinds <- readMutVar tybinds_var
+ ; return $ map freeTvs (bagToList tybinds)
+ }
+ where
+ freeTvs (TcTyVarBind tv ty) = (tv, tyVarsOfType ty)
+\end{code}
+
+%************************************************************************
+%* *