[es6] implement destructuring assignment

src/prettyprinter.cc

Index: src/prettyprinter.cc
diff --git a/src/prettyprinter.cc b/src/prettyprinter.cc
index be241162dd73f99a15b5598ef1d3627b1f7fd9e7..642e2793a74c97481d04fde94c31e17d3a1cd1ac 100644
--- a/src/prettyprinter.cc
+++ b/src/prettyprinter.cc
@@ -13,6 +13,15 @@
 namespace v8 {
 namespace internal {
 
+#define RETURN_IF_FIND_NODE(node) \
+  do {                            \
+    AstNode* tmp = node;          \
+    if (tmp != nullptr) {         \
+      Find(tmp);                  \
+      return;                     \
+    }                             \
+  } while (false)
+
 CallPrinter::CallPrinter(Isolate* isolate) {
   output_ = NULL;
   size_ = 0;
@@ -274,6 +283,7 @@ void CallPrinter::VisitVariableProxy(VariableProxy* node) {
 
 
 void CallPrinter::VisitAssignment(Assignment* node) {
+  RETURN_IF_FIND_NODE(node->destructuring_assignment());
   Find(node->target());
   Find(node->value());
 }
@@ -780,6 +790,7 @@ void PrettyPrinter::VisitVariableProxy(VariableProxy* node) {
 
 
 void PrettyPrinter::VisitAssignment(Assignment* node) {
+  RETURN_IF_VISIT_NODE(node->destructuring_assignment());
   Visit(node->target());
   Print(" %s ", Token::String(node->op()));
   Visit(node->value());
@@ -1529,6 +1540,7 @@ void AstPrinter::VisitVariableProxy(VariableProxy* node) {
 
 void AstPrinter::VisitAssignment(Assignment* node) {
   IndentedScope indent(this, Token::Name(node->op()), node->position());
+  RETURN_IF_VISIT_NODE(node->destructuring_assignment());
   Visit(node->target());
   Visit(node->value());
 }