Add missing labels.pop() to allow re-using labels in a block

Issue #15

acorn.js

@@ -1233,6 +1233,7 @@
         var kind = tokType.isLoop ? "loop" : tokType === _switch ? "switch" : null;
         labels.push({name: maybeName, kind: kind});
         node.body = parseStatement();
+        labels.pop();
         node.label = expr;
         return finishNode(node, "LabeledStatement");
       } else {

index.html

@@ -902,6 +902,7 @@ Identifier node, we switch to interpreting it as a label.</p>             </td>
         <span class="kd">var</span> <span class="nx">kind</span> <span class="o">=</span> <span class="nx">tokType</span><span class="p">.</span><span class="nx">isLoop</span> <span class="o">?</span> <span class="s2">&quot;loop&quot;</span> <span class="o">:</span> <span class="nx">tokType</span> <span class="o">===</span> <span class="nx">_switch</span> <span class="o">?</span> <span class="s2">&quot;switch&quot;</span> <span class="o">:</span> <span class="kc">null</span><span class="p">;</span>
         <span class="nx">labels</span><span class="p">.</span><span class="nx">push</span><span class="p">({</span><span class="nx">name</span><span class="o">:</span> <span class="nx">maybeName</span><span class="p">,</span> <span class="nx">kind</span><span class="o">:</span> <span class="nx">kind</span><span class="p">});</span>
         <span class="nx">node</span><span class="p">.</span><span class="nx">body</span> <span class="o">=</span> <span class="nx">parseStatement</span><span class="p">();</span>
+        <span class="nx">labels</span><span class="p">.</span><span class="nx">pop</span><span class="p">();</span>
         <span class="nx">node</span><span class="p">.</span><span class="nx">label</span> <span class="o">=</span> <span class="nx">expr</span><span class="p">;</span>
         <span class="k">return</span> <span class="nx">finishNode</span><span class="p">(</span><span class="nx">node</span><span class="p">,</span> <span class="s2">&quot;LabeledStatement&quot;</span><span class="p">);</span>
       <span class="p">}</span> <span class="k">else</span> <span class="p">{</span>

test/tests.js

@@ -26029,6 +26029,42 @@ test("'a\\u0026b'", {
   ]
 });
 
+test("foo: 10; foo: 20;", {
+  type: "Program",
+  body: [
+    {
+      type: "LabeledStatement",
+      body: {
+        type: "ExpressionStatement",
+        expression: {
+          type: "Literal",
+          value: 10,
+          raw: "10"
+        }
+      },
+      label: {
+        type: "Identifier",
+        name: "foo"
+      }
+    },
+    {
+      type: "LabeledStatement",
+      body: {
+        type: "ExpressionStatement",
+        expression: {
+          type: "Literal",
+          value: 20,
+          raw: "20"
+        }
+      },
+      label: {
+        type: "Identifier",
+        name: "foo"
+      }
+    }
+  ]
+});
+
 // Failure tests
 
 testFail("{",