diff --git a/src/celpy/evaluation.py b/src/celpy/evaluation.py
index 9719cdb..ac0e109 100644
--- a/src/celpy/evaluation.py
+++ b/src/celpy/evaluation.py
@@ -3415,7 +3415,7 @@ def member_dot_arg(self, tree: TranspilerTree) -> None:
                 ).transpiled.split(".")
             else:
                 raise CELSyntaxError(  # pragma: no cover
-                    "no bind variable in {property_name_token.value} macro",
+                    f"no bind variable in {property_name_token.value} macro",
                     line=tree.meta.line,
                     column=tree.meta.column,
                 )