diff --git a/visidata/features/rename_col_cascade.py b/visidata/features/rename_col_cascade.py
index f6c43b05f..bab43e932 100644
--- a/visidata/features/rename_col_cascade.py
+++ b/visidata/features/rename_col_cascade.py
@@ -23,7 +23,8 @@ def setName(col, newname):
         for c in col.sheet.columns:
             if isinstance(c, ExprColumn):
                 parsed_expr = ast.parse(c.expr)
+                canon_expr = ast.unparse(parsed_expr)
                 new_expr = ast.unparse(Renamer(col.name, newname).visit(parsed_expr))
-                if new_expr != parsed_expr:
+                if new_expr != canon_expr:
                     vd.addUndo(setattr, c, 'expr', c.expr)
                     c.expr = new_expr