Non-int conversion to Py_hash_t.

Still requires the more conservative __index__ here rather than a possibly
truncating __int__ because this is used in a context where floating point
values should probably be treated specially.

This fixes Github issue #2752.

Cython/Utility/ModuleSetupCode.c

@@ -651,10 +651,10 @@ static CYTHON_INLINE void * PyThread_tss_get(Py_tss_t *key) {
 #if PY_VERSION_HEX < 0x030200A4
   typedef long Py_hash_t;
   #define __Pyx_PyInt_FromHash_t PyInt_FromLong
-  #define __Pyx_PyInt_AsHash_t   PyInt_AsLong
+  #define __Pyx_PyInt_AsHash_t   __Pyx_PyIndex_AsHash_t
 #else
   #define __Pyx_PyInt_FromHash_t PyInt_FromSsize_t
-  #define __Pyx_PyInt_AsHash_t   PyInt_AsSsize_t
+  #define __Pyx_PyInt_AsHash_t   __Pyx_PyIndex_AsSsize_t
 #endif
 
 #if PY_MAJOR_VERSION >= 3

Cython/Utility/TypeConversion.c

@@ -102,6 +102,7 @@ static CYTHON_INLINE PyObject* __Pyx_PyNumber_IntOrLong(PyObject* x);
 
 static CYTHON_INLINE Py_ssize_t __Pyx_PyIndex_AsSsize_t(PyObject*);
 static CYTHON_INLINE PyObject * __Pyx_PyInt_FromSize_t(size_t);
+static CYTHON_INLINE Py_hash_t __Pyx_PyIndex_AsHash_t(PyObject*);
 
 #if CYTHON_ASSUME_SAFE_MACROS
 #define __pyx_PyFloat_AsDouble(x) (PyFloat_CheckExact(x) ? PyFloat_AS_DOUBLE(x) : PyFloat_AsDouble(x))
@@ -420,6 +421,25 @@ static CYTHON_INLINE Py_ssize_t __Pyx_PyIndex_AsSsize_t(PyObject* b) {
 }
 
 
+static CYTHON_INLINE Py_hash_t __Pyx_PyIndex_AsHash_t(PyObject* o) {
+  if (sizeof(Py_hash_t) == sizeof(Py_ssize_t)) {
+    return __Pyx_PyIndex_AsSsize_t(o);
+#if PY_MAJOR_VERSION < 3
+  } else if (likely(PyInt_CheckExact(o))) {
+    return PyInt_AS_LONG(o);
+#endif
+  } else {
+    Py_ssize_t ival;
+    PyObject *x;
+    x = PyNumber_Index(o);
+    if (!x) return -1;
+    ival = PyInt_AsLong(x);
+    Py_DECREF(x);
+    return ival;
+  }
+}
+
+
 static CYTHON_INLINE PyObject * __Pyx_PyBool_FromLong(long b) {
   return b ? __Pyx_NewRef(Py_True) : __Pyx_NewRef(Py_False);
 }

tests/run/py_hash_t.pyx

@@ -2,12 +2,30 @@
 cimport cython
 
 
+class IntLike(object):
+  def __init__(self, value):
+    self.value = value
+  def __index__(self):
+    return self.value
+
+
 def assign_py_hash_t(x):
     """
     >>> assign_py_hash_t(12)
     12
     >>> assign_py_hash_t(-12)
     -12
+
+    >>> assign_py_hash_t(IntLike(-3))
+    -3
+    >>> assign_py_hash_t(IntLike(1 << 100))  # doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    OverflowError: ...
+    >>> assign_py_hash_t(IntLike(1.5))  # doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    TypeError: __index__ ... (type float)
     """
     cdef Py_hash_t h = x
     return h