//env.next refers to the lexically enclosing environment in which
//the polymorphic signature call environment is nested.
switch (env.next.tree.getTag()) {
case JCTree.TYPECAST:
JCTypeCast castTree = (JCTypeCast)env.next.tree;
restype = (TreeInfo.skipParens(castTree.expr) == env.tree) ?
castTree.clazz.type :
syms.objectType;
break;
case JCTree.EXEC: