Introduced the oddly-missing PyList_CheckExact(), and used it to replace

a hard-coded type check.

Include/listobject.h

@@ -27,6 +27,7 @@ typedef struct {
 extern DL_IMPORT(PyTypeObject) PyList_Type;
 
 #define PyList_Check(op) PyObject_TypeCheck(op, &PyList_Type)
+#define PyList_CheckExact(op) ((op)->ob_type == &PyList_Type)
 
 extern DL_IMPORT(PyObject *) PyList_New(int size);
 extern DL_IMPORT(int) PyList_Size(PyObject *);

Python/ceval.c

@@ -989,7 +989,7 @@ eval_frame(PyFrameObject *f)
 		case BINARY_SUBSCR:
 			w = POP();
 			v = POP();
-			if (v->ob_type == &PyList_Type && PyInt_CheckExact(w)) {
+			if (PyList_CheckExact(v) && PyInt_CheckExact(w)) {
 				/* INLINE: list[int] */
 				long i = PyInt_AsLong(w);
 				if (i < 0)