diff --git a/artiq/compiler/transforms/inferencer.py b/artiq/compiler/transforms/inferencer.py
index 21bc7c62a..2e0bd629b 100644
--- a/artiq/compiler/transforms/inferencer.py
+++ b/artiq/compiler/transforms/inferencer.py
@@ -1017,7 +1017,7 @@ class Inferencer(algorithm.Visitor):
 
             diag = diagnostic.Diagnostic("error",
                 "decorators are not supported", {},
-                node.at_locs[index], [decorator.loc])
+                node.at_locs[index], [])
             self.engine.process(diag)
 
         try: