public void visitFunctionDefinitionNode(ASTPtFunctionDefinitionNode node)
throws IllegalActionException {
ASTPtRootNode cloneTree;
ParseTreeSpecializer specializer = new ParseTreeSpecializer();
cloneTree = specializer.specialize(node.getExpressionTree(), node
.getArgumentNameList(), _scope);
// Infer the return type.
if (_typeInference == null) {
_typeInference = new ParseTreeTypeInference();