import Outputable
import StaticFlags ( opt_PprStyle_Debug )
import BasicTypes ( isAlwaysActive )
-import Util ( mapAccumL, lengthExceeds )
+import Util ( lengthExceeds )
import UniqFM
+
+import Data.List
\end{code}
addBinder env@(CS cs in_scope sub) v
| not (v `elemInScopeSet` in_scope) = (CS cs (extendInScopeSet in_scope v) sub, v)
| isId v = (CS cs (extendInScopeSet in_scope v') (extendVarEnv sub v v'), v')
- | not (isId v) = WARN( True, ppr v )
+ | otherwise = WARN( True, ppr v )
(CS emptyUFM in_scope sub, v)
-- This last case is the unusual situation where we have shadowing of
-- a type variable; we have to discard the CSE mapping