fix bug #171: a first attempt

fix bug #171: a first attempt

src/runtime/list.cpp

@@ -396,7 +396,8 @@ Box* listContains(BoxedList* self, Box* elt) {
     for (int i = 0; i < size; i++) {
         Box* e = self->elts->elts[i];
         Box* cmp = compareInternal(e, elt, AST_TYPE::Eq, NULL);
-        bool b = nonzero(cmp);
+        bool identity_eq = e == elt;
+        bool b = nonzero(cmp) || identity_eq;
         if (b)
             return True;
     }
@@ -518,7 +519,8 @@ Box* _listCmp(BoxedList* lhs, BoxedList* rhs, AST_TYPE::AST_TYPE op_type) {
     int n = std::min(lsz, rsz);
     for (int i = 0; i < n; i++) {
         Box* is_eq = compareInternal(lhs->elts->elts[i], rhs->elts->elts[i], AST_TYPE::Eq, NULL);
-        bool bis_eq = nonzero(is_eq);
+        bool identity_eq = lhs->elts->elts[i] == rhs->elts->elts[i];
+        bool bis_eq = nonzero(is_eq) || identity_eq;
 
         if (bis_eq)
             continue;