diff --git a/logic.py b/logic.py index 338e5aac2..75c461e8f 100644 --- a/logic.py +++ b/logic.py @@ -796,6 +796,8 @@ def is_variable(x): def unify_var(var, x, s): if var in s: return unify(s[var], x, s) + elif x in s: + return unify(var, s[x], s) elif occur_check(var, x, s): return None else: