diff --git a/pymbolic/parser.py b/pymbolic/parser.py
index 8f199b3e31ef3876208eaf0c18fc382540ce9831..5f69c06c02e7976cbcbc6177a668a81867e1c4fc 100644
--- a/pymbolic/parser.py
+++ b/pymbolic/parser.py
@@ -384,6 +384,8 @@ class Parser(object):
                 left_exp = _join_to_slice(left_exp, next_expr)
                 pstate.assign(expr_pstate)
 
+            did_something = True
+
         elif next_tag is _comma and _PREC_COMMA > min_precedence:
             # The precedence makes the comma left-associative.