Fix unique tuple unpacking checks

Author: reidenong

Python/bytecodes.c

@@ -1675,6 +1675,7 @@ dummy_func(
             PyObject *seq_o = PyStackRef_AsPyObjectBorrow(seq);
             assert(PyTuple_CheckExact(seq_o));
             DEOPT_IF(PyTuple_GET_SIZE(seq_o) != oparg);
+            DEOPT_IF(!_PyObject_IsUniquelyReferenced(seq_o));
             STAT_INC(UNPACK_SEQUENCE, hit);
             PyObject **items = _PyTuple_ITEMS(seq_o);
             for (int i = oparg; --i >= 0; ) {

Python/executor_cases.c.h

@@ -1350,8 +1350,8 @@ dummy_func(void) {
     }
 
     op(_UNPACK_SEQUENCE_TUPLE, (seq -- values[oparg])) {
-        if (PyJitRef_IsUnique(seq)) {
-            REPLACE_OP((this_instr), _UNPACK_SEQUENCE_UNIQUE_TUPLE, oparg, 0);
+        if (PyJitRef_IsUnique(seq) && sym_tuple_length(seq) == oparg) {
+            ADD_OP(_UNPACK_SEQUENCE_UNIQUE_TUPLE, oparg, 0);
         }
         for (int i = 0; i < oparg; i++) {
             values[i] = sym_tuple_getitem(ctx, seq, oparg - i - 1);