Throw an error if a Function node adds an input event listener

nodes/core/core/80-function.js

@@ -83,6 +83,9 @@ module.exports = function(RED) {
                     sendResults(node, id, msgs);
                 },
                 on: function() {
+                    if (arguments[0] === "input") {
+                        throw new Error(RED._("function.error.inputListener"));
+                    }
                     node.on.apply(node, arguments);
                 },
                 status: function() {

nodes/core/locales/en-US/messages.json

@@ -141,6 +141,9 @@
             "function": "Function",
             "outputs": "Outputs"
         },
+        "error": {
+            "inputListener":"Cannot add listener to 'input' event within Function"
+        },
         "tip": "See the Info tab for help writing functions."
     },
     "template": {