Finish AppF shrinking

compiler/src/l3/CPSOptimizer.scala

@@ -75,8 +75,11 @@ abstract class CPSOptimizer[T <: CPSTreeModule { type Name = Symbol }]
       fun match {
         case AtomN(n) if s.fEnv.contains(n) && s.appliedOnce(n) =>
           // Inline
-          val fun = s.fEnv.get(n)
-          ???
+          val fun = s.fEnv(n)
+          val newState = s.withASubst(fun.args, args)
+                          .withCSubst(fun.retC, retC)
+          val newBody = shrink(fun.body, newState)
+          newBody
         case _ => tree
       }