Fix optional patterns without default values for the given positions.

Mathics3 · Nov 19, 2024 · c1999ce · c1999ce
1 parent 85ad0f5
commit c1999ce
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/mathics/core/pattern.py b/mathics/core/pattern.py
@@ -724,8 +724,11 @@ def match_expression_with_one_identity(
                 result = defaultvalue_expr.evaluate(evaluation)
                 assert result is not None
                 if result.sameQ(defaultvalue_expr):
-                    return
-                optionals[key] = result
+                    # The optional pattern has no default value
+                    # for the given position
+                    new_pattern = pat_elem
+                else:
+                    optionals[key] = result
             else:
                 return
         elif new_pattern is not None: