diff --git a/src/root.js b/src/root.js
index d11bc005d..38bc15833 100644
--- a/src/root.js
+++ b/src/root.js
@@ -232,6 +232,17 @@ RootPrototype.loadSync = function loadSync(filename, options) {
     return this.load(filename, options, SYNC);
 };
 
+/**
+ * @override
+ */
+RootPrototype.resolveAll = function resolveAll() {
+    if (this.deferred.length)
+        throw Error("unresolvable extensions: " + this.deferred.map(function(field) {
+            return "'extend " + field.extend + "' in " + field.parent.getFullName();
+        }).join(", "));
+    return Namespace.prototype.resolveAll.call(this);
+};
+
 /**
  * Handles a deferred declaring extension field by creating a sister field to represent it within its extended type.
  * @param {Field} field Declaring extension field witin the declaring type
diff --git a/tests/data/extend.proto b/tests/data/extend.proto
new file mode 100644
index 000000000..7bbb48fcb
--- /dev/null
+++ b/tests/data/extend.proto
@@ -0,0 +1,16 @@
+syntax = "proto3";
+
+message A {
+    message B {
+        message One {
+            extensions 1000 to max;
+        }
+    }
+    message C {
+        message Two {
+            extend B.One {
+                Two two = 1000;
+            }
+        }
+    }
+}
diff --git a/tests/extend.js b/tests/extend.js
new file mode 100644
index 000000000..04c798b2e
--- /dev/null
+++ b/tests/extend.js
@@ -0,0 +1,15 @@
+var tape = require("tape");
+
+var protobuf  = require("..");
+
+tape.test("extensions", function(test) {
+
+    protobuf.load("tests/data/extend.proto", function(err, root) {
+        if (err)
+            return test.fail(err.message);
+        root.resolveAll();
+        test.pass("should parse and resolve without errors");
+        test.end();
+    });
+
+});
\ No newline at end of file