Issue #870 ... placeholders in destructuring assignment.

lib/nodes.js

@@ -1134,6 +1134,9 @@
       value = this.value;
       objects = this.variable.base.objects;
       if (!(olen = objects.length)) {
+        if (top) {
+          return false;
+        }
         code = value.compile(o);
         if (o.level >= LEVEL_OP) {
           return "(" + code + ")";
@@ -1208,7 +1211,7 @@
       if (!top) {
         assigns.push(vvar);
       }
-      code = assigns.join(', ');
+      code = (compact(assigns)).join(', ');
       if (o.level < LEVEL_LIST) {
         return code;
       } else {

src/nodes.coffee

@@ -908,6 +908,7 @@ exports.Assign = class Assign extends Base
     {value}   = this
     {objects} = @variable.base
     unless olen = objects.length
+      return false if top
       code = value.compile o
       return if o.level >= LEVEL_OP then "(#{code})" else code
     isObject = @variable.isObject()
@@ -968,7 +969,7 @@ exports.Assign = class Assign extends Base
         val = new Value new Literal(vvar), [new (if acc then Access else Index) idx]
       assigns.push new Assign(obj, val, null, param: @param).compile o, LEVEL_TOP
     assigns.push vvar unless top
-    code = assigns.join ', '
+    code = (compact assigns).join ', '
     if o.level < LEVEL_LIST then code else "(#{code})"
 
   # When compiling a conditional assignment, take care to ensure that the