diff --git a/lib/beefcake.rb b/lib/beefcake.rb
index 705178b..059b6c7 100644
--- a/lib/beefcake.rb
+++ b/lib/beefcake.rb
@@ -72,7 +72,7 @@ def encode(buf = Buffer.new)
         fields.values.sort.each do |fld|
           if fld.opts[:packed]
             bytes = encode!(Buffer.new, fld, 0)
-            buf.append_info(Buffer.wire_for(fld.type), fld.fn)
+            buf.append_info(fld.fn, Buffer.wire_for(fld.type))
             buf.append_uint64(bytes.length)
             buf << bytes
           else
diff --git a/test/message_test.rb b/test/message_test.rb
index 4947bdd..6e2a293 100644
--- a/test/message_test.rb
+++ b/test/message_test.rb
@@ -184,7 +184,7 @@ def test_encode_packed_repeated_field
     buf = Beefcake::Buffer.new
 
     # Varint
-    buf.append_info(0, 1)
+    buf.append_info(1, 0)
 
     # Give size in bytes
     buf.append_uint64 5