Use existing pointer hash logic

Author: rhettinger

Doc/library/stdtypes.rst

@@ -739,7 +739,7 @@ number, :class:`float`, or :class:`complex`::
        """Compute the hash of a float x."""
 
        if math.isnan(x):
-           return id(x)
+           return super().__hash__()
        elif math.isinf(x):
            return sys.hash_info.inf if x > 0 else -sys.hash_info.inf
        else:

Lib/_pydecimal.py

@@ -951,7 +951,7 @@ def __hash__(self):
             if self.is_snan():
                 raise TypeError('Cannot hash a signaling NaN value.')
             elif self.is_nan():
-                return id(self)
+                return super().__hash__()
             else:
                 if self._sign:
                     return -_PyHASH_INF

Modules/_decimal/_decimal.c

@@ -4554,7 +4554,7 @@ _dec_hash(PyDecObject *v)
             return -1;
         }
         else if (mpd_isnan(MPD(v))) {
-            return (Py_hash_t) v;
+            return _Py_HashPointer(v);
         }
         else {
             return py_hash_inf * mpd_arith_sign(MPD(v));
@@ -5938,5 +5938,3 @@ PyInit__decimal(void)
 
     return NULL; /* GCOV_NOT_REACHED */
 }
-
-

Python/pyhash.c

@@ -86,6 +86,8 @@ static Py_ssize_t hashstats[Py_HASH_STATS_MAX + 1] = {0};
 
    */
 
+Py_hash_t _Py_HashPointer(const void *);
+
 Py_hash_t
 _Py_HashDouble(PyObject *inst, double v)
 {
@@ -97,7 +99,7 @@ _Py_HashDouble(PyObject *inst, double v)
         if (Py_IS_INFINITY(v))
             return v > 0 ? _PyHASH_INF : -_PyHASH_INF;
         else
-            return (Py_hash_t) inst;
+            return _Py_HashPointer(inst);
     }
 
     m = frexp(v, &e);