diff --git a/_extensions/cps/__init__.py b/_extensions/cps/__init__.py
index 378e23f..e83d7c5 100644
--- a/_extensions/cps/__init__.py
+++ b/_extensions/cps/__init__.py
@@ -487,7 +487,7 @@ def resolve_xref(self, env, fromdocname, builder,
             _, docname, refnode = c
             qualified = not short and len(attr.instances) > 1
 
-        label = refnode['names'][0]
+        label = nodes.make_id(refnode['names'][0])
 
         cont = nodes.literal('', name, classes=['attribute'])
         if qualified: