+\begin{code}
+type DeprecationEnv = NameEnv DeprecTxt -- Give reason for deprecation
+
+type GlobalRdrEnv = RdrNameEnv [Name] -- The list is because there may be name clashes
+ -- These only get reported on lookup,
+ -- not on construction
+
+data GenAvailInfo name = Avail name -- An ordinary identifier
+ | AvailTC name -- The name of the type or class
+ [name] -- The available pieces of type/class.
+ -- NB: If the type or class is itself
+ -- to be in scope, it must be in this list.
+ -- Thus, typically: AvailTC Eq [Eq, ==, /=]
+ deriving( Eq )
+ -- Equality used when deciding if the interface has changed
+
+type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
+type AvailInfo = GenAvailInfo Name
+type RdrAvailInfo = GenAvailInfo OccName
+type Avails = [AvailInfo]
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{The persistent compiler state}
+%* *
+%************************************************************************
+
+\begin{code}