fix up types.toStatement and return an expressionStatement if all else fails

lib/6to5/types/index.js

@@ -119,18 +119,12 @@ t.toStatement = function (node, ignore) {
   } else if (t.isFunction(node)) {
     mustHaveId = true;
     newType = "FunctionDeclaration";
+  } else {
+    return t.expressionStatement(node);
   }
 
   if (mustHaveId && !node.id) {
-    newType = false;
-  }
-
-  if (!newType) {
-    if (ignore) {
-      return false;
-    } else {
-      throw new Error("cannot turn " + node.type + " to a statement");
-    }
+    throw new Error("the type " + node.type + " needs an id in order to be transformed into a statement");
   }
 
   node.type = newType;