[es6] implement destructuring assignment [clean diff]

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index dac59b7d4437ee5fd406740cf7023277dfecd0f6..61c169965d48378954a2fc30d7d91f93936ebb41 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -3607,10 +3607,26 @@ Expression* Parser::DesugarDestructuringAssignment(Expression* expr) {
   // TODO(caitp): implement the desugaring
   DCHECK(expr->IsAssignment());
   Assignment* assign = expr->AsAssignment();
-  while (assign->value()->IsAssignment()) {
-    assign = assign->value()->AsAssignment();
+  Expression* value = assign->value();
+  Expression* target = assign->target();
+  Variable* result = nullptr;
+  if (value->IsAssignment()) {

[caitp (gmail), 2015/10/19 11:17:39]

I'll make all of this completion-value-saving code much simpler, shortly

+    value = DesugarDestructuringAssignment(value);
+    if (value->IsDoExpression()) {
+      result = value->AsDoExpression()->result()->var();
+    }
+  }
+  if (target->IsObjectLiteral() || target->IsArrayLiteral()) {
+    Block* block = factory()->NewBlock(nullptr, 8, false, expr->position());
+    bool ok = true;
+    result = PatternRewriter::RewriteDestructuringAssignment(
+        this, block, target, value, result, &ok);
+    DCHECK_EQ(ok, true);
+    DCHECK_NOT_NULL(result);
+    return factory()->NewDoExpression(block, result, expr->position());
   }
-  return assign->value();
+
+  return expr;
 }