1 files changed, 8 insertions, 2 deletions
diff --git a/lib/handlebars/compiler/visitor.js b/lib/handlebars/compiler/visitor.js
index 47f86e0..89dd632 100644
--- a/lib/handlebars/compiler/visitor.js
+++ b/lib/handlebars/compiler/visitor.js
@@ -12,8 +12,9 @@ Visitor.prototype = {
   acceptKey: function(node, name) {
     let value = this.accept(node[name]);
     if (this.mutating) {
-      // Hacky sanity check:
-      if (value && typeof value.type !== 'string') {
+      // Hacky sanity check: This may have a few false positives for type for the helper
+      // methods but will generally do the right thing without a lot of overhead.
+      if (value && !Visitor.prototype[value.type]) {
         throw new Exception('Unexpected node type "' + value.type + '" found when accepting ' + name + ' on ' + node.type);
       }
       node[name] = value;
@@ -49,6 +50,11 @@ Visitor.prototype = {
       return;
     }
 
+    /* istanbul ignore next: Sanity code */
+    if (!this[object.type]) {
+      throw new Exception('Unknown type: ' + object.type, object);
+    }
+
     if (this.current) {
       this.parents.unshift(this.current);
     }