Fix HasInstance to recurse the prototype hierarchy

error_test.go

@@ -0,0 +1,15 @@
+package otto
+
+import (
+	. "./terst"
+	"testing"
+)
+
+func TestError_instanceof(t *testing.T) {
+	Terst(t)
+
+	test := runTest()
+	test(`
+        (new TypeError()) instanceof Error
+    `, "true")
+}

type_function.go

@@ -86,11 +86,16 @@ func (self *_object) HasInstance(of Value) bool {
 	if !prototype.IsObject() {
 		panic(newTypeError())
 	}
-	ofPrototype := of._object().prototype
-	if ofPrototype == nil {
-		return false
+	prototypeObject := prototype._object()
+
+	value := of._object().prototype
+	for value != nil {
+		if value == prototypeObject {
+			return true
+		}
+		value = value.prototype
 	}
-	return ofPrototype == prototype._object()
+	return false
 }
 
 type _functionSignature string