diff --git a/Modules/blake2module.c b/Modules/blake2module.c
index 6723e7de4675a5..016c834c01bbe2 100644
--- a/Modules/blake2module.c
+++ b/Modules/blake2module.c
@@ -366,6 +366,8 @@ typedef struct {
     PyMutex mutex;
 } Blake2Object;
 
+#define _Blake2Object_CAST(op)  ((Blake2Object *)(op))
+
 #include "clinic/blake2module.c.h"
 
 /*[clinic input]
@@ -849,24 +851,27 @@ static PyMethodDef py_blake2b_methods[] = {
 
 
 static PyObject *
-py_blake2b_get_name(Blake2Object *self, void *closure)
+py_blake2b_get_name(PyObject *op, void *Py_UNUSED(closure))
 {
+    Blake2Object *self = _Blake2Object_CAST(op);
     return PyUnicode_FromString(is_blake2b(self->impl) ? "blake2b" : "blake2s");
 }
 
 
 
 static PyObject *
-py_blake2b_get_block_size(Blake2Object *self, void *closure)
+py_blake2b_get_block_size(PyObject *op, void *Py_UNUSED(closure))
 {
+    Blake2Object *self = _Blake2Object_CAST(op);
     return PyLong_FromLong(is_blake2b(self->impl) ? HACL_HASH_BLAKE2B_BLOCK_BYTES : HACL_HASH_BLAKE2S_BLOCK_BYTES);
 }
 
 
 
 static PyObject *
-py_blake2b_get_digest_size(Blake2Object *self, void *closure)
+py_blake2b_get_digest_size(PyObject *op, void *Py_UNUSED(closure))
 {
+    Blake2Object *self = _Blake2Object_CAST(op);
     switch (self->impl) {
 #if HACL_CAN_COMPILE_SIMD256
         case Blake2b_256:
@@ -887,15 +892,13 @@ py_blake2b_get_digest_size(Blake2Object *self, void *closure)
 
 
 static PyGetSetDef py_blake2b_getsetters[] = {
-    {"name", (getter)py_blake2b_get_name,
-        NULL, NULL, NULL},
-    {"block_size", (getter)py_blake2b_get_block_size,
-        NULL, NULL, NULL},
-    {"digest_size", (getter)py_blake2b_get_digest_size,
-        NULL, NULL, NULL},
-    {NULL}
+    {"name", py_blake2b_get_name, NULL, NULL, NULL},
+    {"block_size", py_blake2b_get_block_size, NULL, NULL, NULL},
+    {"digest_size", py_blake2b_get_digest_size, NULL, NULL, NULL},
+    {NULL}  /* Sentinel */
 };
 
+
 static int
 py_blake2_clear(PyObject *op)
 {
diff --git a/Modules/md5module.c b/Modules/md5module.c
index ef9163e8be5b6c..d86c8e555012d7 100644
--- a/Modules/md5module.c
+++ b/Modules/md5module.c
@@ -54,6 +54,8 @@ typedef struct {
     Hacl_Hash_MD5_state_t *hash_state;
 } MD5object;
 
+#define _MD5object_CAST(op)     ((MD5object *)(op))
+
 #include "clinic/md5module.c.h"
 
 
@@ -72,7 +74,7 @@ md5_get_state(PyObject *module)
 static MD5object *
 newMD5object(MD5State * st)
 {
-    MD5object *md5 = (MD5object *)PyObject_GC_New(MD5object, st->md5_type);
+    MD5object *md5 = PyObject_GC_New(MD5object, st->md5_type);
     if (!md5) {
         return NULL;
     }
@@ -91,10 +93,11 @@ MD5_traverse(PyObject *ptr, visitproc visit, void *arg)
 }
 
 static void
-MD5_dealloc(MD5object *ptr)
+MD5_dealloc(PyObject *op)
 {
+    MD5object *ptr = _MD5object_CAST(op);
     Hacl_Hash_MD5_free(ptr->hash_state);
-    PyTypeObject *tp = Py_TYPE((PyObject*)ptr);
+    PyTypeObject *tp = Py_TYPE(op);
     PyObject_GC_UnTrack(ptr);
     PyObject_GC_Del(ptr);
     Py_DECREF(tp);
@@ -224,36 +227,27 @@ static PyMethodDef MD5_methods[] = {
 };
 
 static PyObject *
-MD5_get_block_size(PyObject *self, void *closure)
+MD5_get_block_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(MD5_BLOCKSIZE);
 }
 
 static PyObject *
-MD5_get_name(PyObject *self, void *closure)
+MD5_get_name(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyUnicode_FromStringAndSize("md5", 3);
 }
 
 static PyObject *
-md5_get_digest_size(PyObject *self, void *closure)
+md5_get_digest_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(MD5_DIGESTSIZE);
 }
 
 static PyGetSetDef MD5_getseters[] = {
-    {"block_size",
-     (getter)MD5_get_block_size, NULL,
-     NULL,
-     NULL},
-    {"name",
-     (getter)MD5_get_name, NULL,
-     NULL,
-     NULL},
-    {"digest_size",
-     (getter)md5_get_digest_size, NULL,
-     NULL,
-     NULL},
+    {"block_size", MD5_get_block_size, NULL, NULL, NULL},
+    {"name", MD5_get_name, NULL, NULL, NULL},
+    {"digest_size", md5_get_digest_size, NULL, NULL, NULL},
     {NULL}  /* Sentinel */
 };
 
diff --git a/Modules/sha1module.c b/Modules/sha1module.c
index 34a427a39b5cf8..d0b1e8250770d0 100644
--- a/Modules/sha1module.c
+++ b/Modules/sha1module.c
@@ -55,6 +55,8 @@ typedef struct {
     Hacl_Hash_SHA1_state_t *hash_state;
 } SHA1object;
 
+#define _SHA1object_CAST(op)    ((SHA1object *)(op))
+
 #include "clinic/sha1module.c.h"
 
 
@@ -73,7 +75,7 @@ sha1_get_state(PyObject *module)
 static SHA1object *
 newSHA1object(SHA1State *st)
 {
-    SHA1object *sha = (SHA1object *)PyObject_GC_New(SHA1object, st->sha1_type);
+    SHA1object *sha = PyObject_GC_New(SHA1object, st->sha1_type);
     if (sha == NULL) {
         return NULL;
     }
@@ -93,8 +95,9 @@ SHA1_traverse(PyObject *ptr, visitproc visit, void *arg)
 }
 
 static void
-SHA1_dealloc(SHA1object *ptr)
+SHA1_dealloc(PyObject *op)
 {
+    SHA1object *ptr = _SHA1object_CAST(op);
     Hacl_Hash_SHA1_free(ptr->hash_state);
     PyTypeObject *tp = Py_TYPE(ptr);
     PyObject_GC_UnTrack(ptr);
@@ -217,36 +220,27 @@ static PyMethodDef SHA1_methods[] = {
 };
 
 static PyObject *
-SHA1_get_block_size(PyObject *self, void *closure)
+SHA1_get_block_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(SHA1_BLOCKSIZE);
 }
 
 static PyObject *
-SHA1_get_name(PyObject *self, void *closure)
+SHA1_get_name(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyUnicode_FromStringAndSize("sha1", 4);
 }
 
 static PyObject *
-sha1_get_digest_size(PyObject *self, void *closure)
+sha1_get_digest_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(SHA1_DIGESTSIZE);
 }
 
 static PyGetSetDef SHA1_getseters[] = {
-    {"block_size",
-     (getter)SHA1_get_block_size, NULL,
-     NULL,
-     NULL},
-    {"name",
-     (getter)SHA1_get_name, NULL,
-     NULL,
-     NULL},
-    {"digest_size",
-     (getter)sha1_get_digest_size, NULL,
-     NULL,
-     NULL},
+    {"block_size", SHA1_get_block_size, NULL, NULL, NULL},
+    {"name", SHA1_get_name, NULL, NULL, NULL},
+    {"digest_size", sha1_get_digest_size, NULL, NULL, NULL},
     {NULL}  /* Sentinel */
 };
 
@@ -346,7 +340,7 @@ _sha1_clear(PyObject *module)
 static void
 _sha1_free(void *module)
 {
-    _sha1_clear((PyObject *)module);
+    (void)_sha1_clear((PyObject *)module);
 }
 
 static int
diff --git a/Modules/sha2module.c b/Modules/sha2module.c
index 7d6a1e40243f9d..45fa120cf76758 100644
--- a/Modules/sha2module.c
+++ b/Modules/sha2module.c
@@ -67,6 +67,9 @@ typedef struct {
     Hacl_Hash_SHA2_state_t_512 *state;
 } SHA512object;
 
+#define _SHA256object_CAST(op)  ((SHA256object *)(op))
+#define _SHA512object_CAST(op)  ((SHA512object *)(op))
+
 #include "clinic/sha2module.c.h"
 
 /* We shall use run-time type information in the remainder of this module to
@@ -101,8 +104,7 @@ static void SHA512copy(SHA512object *src, SHA512object *dest)
 static SHA256object *
 newSHA224object(sha2_state *state)
 {
-    SHA256object *sha = (SHA256object *)PyObject_GC_New(
-        SHA256object, state->sha224_type);
+    SHA256object *sha = PyObject_GC_New(SHA256object, state->sha224_type);
     if (!sha) {
         return NULL;
     }
@@ -115,8 +117,7 @@ newSHA224object(sha2_state *state)
 static SHA256object *
 newSHA256object(sha2_state *state)
 {
-    SHA256object *sha = (SHA256object *)PyObject_GC_New(
-        SHA256object, state->sha256_type);
+    SHA256object *sha = PyObject_GC_New(SHA256object, state->sha256_type);
     if (!sha) {
         return NULL;
     }
@@ -129,8 +130,7 @@ newSHA256object(sha2_state *state)
 static SHA512object *
 newSHA384object(sha2_state *state)
 {
-    SHA512object *sha = (SHA512object *)PyObject_GC_New(
-        SHA512object, state->sha384_type);
+    SHA512object *sha = PyObject_GC_New(SHA512object, state->sha384_type);
     if (!sha) {
         return NULL;
     }
@@ -143,8 +143,7 @@ newSHA384object(sha2_state *state)
 static SHA512object *
 newSHA512object(sha2_state *state)
 {
-    SHA512object *sha = (SHA512object *)PyObject_GC_New(
-        SHA512object, state->sha512_type);
+    SHA512object *sha = PyObject_GC_New(SHA512object, state->sha512_type);
     if (!sha) {
         return NULL;
     }
@@ -164,8 +163,9 @@ SHA2_traverse(PyObject *ptr, visitproc visit, void *arg)
 }
 
 static void
-SHA256_dealloc(SHA256object *ptr)
+SHA256_dealloc(PyObject *op)
 {
+    SHA256object *ptr = _SHA256object_CAST(op);
     Hacl_Hash_SHA2_free_256(ptr->state);
     PyTypeObject *tp = Py_TYPE(ptr);
     PyObject_GC_UnTrack(ptr);
@@ -174,8 +174,9 @@ SHA256_dealloc(SHA256object *ptr)
 }
 
 static void
-SHA512_dealloc(SHA512object *ptr)
+SHA512_dealloc(PyObject *op)
 {
+    SHA512object *ptr = _SHA512object_CAST(op);
     Hacl_Hash_SHA2_free_512(ptr->state);
     PyTypeObject *tp = Py_TYPE(ptr);
     PyObject_GC_UnTrack(ptr);
@@ -442,32 +443,35 @@ static PyMethodDef SHA512_methods[] = {
 };
 
 static PyObject *
-SHA256_get_block_size(PyObject *self, void *closure)
+SHA256_get_block_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(SHA256_BLOCKSIZE);
 }
 
 static PyObject *
-SHA512_get_block_size(PyObject *self, void *closure)
+SHA512_get_block_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(SHA512_BLOCKSIZE);
 }
 
 static PyObject *
-SHA256_get_digest_size(SHA256object *self, void *closure)
+SHA256_get_digest_size(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA256object *self = _SHA256object_CAST(op);
     return PyLong_FromLong(self->digestsize);
 }
 
 static PyObject *
-SHA512_get_digest_size(SHA512object *self, void *closure)
+SHA512_get_digest_size(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA512object *self = _SHA512object_CAST(op);
     return PyLong_FromLong(self->digestsize);
 }
 
 static PyObject *
-SHA256_get_name(SHA256object *self, void *closure)
+SHA256_get_name(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA256object *self = _SHA256object_CAST(op);
     if (self->digestsize == 28) {
         return PyUnicode_FromStringAndSize("sha224", 6);
     }
@@ -475,8 +479,9 @@ SHA256_get_name(SHA256object *self, void *closure)
 }
 
 static PyObject *
-SHA512_get_name(SHA512object *self, void *closure)
+SHA512_get_name(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA512object *self = _SHA512object_CAST(op);
     if (self->digestsize == 64) {
         return PyUnicode_FromStringAndSize("sha512", 6);
     }
@@ -484,34 +489,16 @@ SHA512_get_name(SHA512object *self, void *closure)
 }
 
 static PyGetSetDef SHA256_getseters[] = {
-    {"block_size",
-     (getter)SHA256_get_block_size, NULL,
-     NULL,
-     NULL},
-    {"name",
-     (getter)SHA256_get_name, NULL,
-     NULL,
-     NULL},
-    {"digest_size",
-     (getter)SHA256_get_digest_size, NULL,
-     NULL,
-     NULL},
+    {"block_size", SHA256_get_block_size, NULL, NULL, NULL},
+    {"name", SHA256_get_name, NULL, NULL, NULL},
+    {"digest_size", SHA256_get_digest_size, NULL, NULL, NULL},
     {NULL}  /* Sentinel */
 };
 
 static PyGetSetDef SHA512_getseters[] = {
-    {"block_size",
-     (getter)SHA512_get_block_size, NULL,
-     NULL,
-     NULL},
-    {"name",
-     (getter)SHA512_get_name, NULL,
-     NULL,
-     NULL},
-    {"digest_size",
-     (getter)SHA512_get_digest_size, NULL,
-     NULL,
-     NULL},
+    {"block_size", SHA512_get_block_size, NULL, NULL, NULL},
+    {"name", SHA512_get_name, NULL, NULL, NULL},
+    {"digest_size", SHA512_get_digest_size, NULL, NULL, NULL},
     {NULL}  /* Sentinel */
 };
 
@@ -818,7 +805,7 @@ _sha2_clear(PyObject *module)
 static void
 _sha2_free(void *module)
 {
-    _sha2_clear((PyObject *)module);
+    (void)_sha2_clear((PyObject *)module);
 }
 
 /* Initialize this module. */
diff --git a/Modules/sha3module.c b/Modules/sha3module.c
index b13e6a9de10114..72a11602b0e1fd 100644
--- a/Modules/sha3module.c
+++ b/Modules/sha3module.c
@@ -66,6 +66,8 @@ typedef struct {
     Hacl_Hash_SHA3_state_t *hash_state;
 } SHA3object;
 
+#define _SHA3object_CAST(op)    ((SHA3object *)(op))
+
 #include "clinic/sha3module.c.h"
 
 static SHA3object *
@@ -167,8 +169,9 @@ py_sha3_new_impl(PyTypeObject *type, PyObject *data, int usedforsecurity)
 /* Internal methods for a hash object */
 
 static int
-SHA3_clear(SHA3object *self)
+SHA3_clear(PyObject *op)
 {
+    SHA3object *self = _SHA3object_CAST(op);
     if (self->hash_state != NULL) {
         Hacl_Hash_SHA3_free(self->hash_state);
         self->hash_state = NULL;
@@ -177,7 +180,7 @@ SHA3_clear(SHA3object *self)
 }
 
 static void
-SHA3_dealloc(SHA3object *self)
+SHA3_dealloc(PyObject *self)
 {
     PyTypeObject *tp = Py_TYPE(self);
     PyObject_GC_UnTrack(self);
@@ -303,15 +306,16 @@ static PyMethodDef SHA3_methods[] = {
 
 
 static PyObject *
-SHA3_get_block_size(SHA3object *self, void *closure)
+SHA3_get_block_size(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA3object *self = _SHA3object_CAST(op);
     uint32_t rate = Hacl_Hash_SHA3_block_len(self->hash_state);
     return PyLong_FromLong(rate);
 }
 
 
 static PyObject *
-SHA3_get_name(SHA3object *self, void *closure)
+SHA3_get_name(PyObject *self, void *Py_UNUSED(closure))
 {
     PyTypeObject *type = Py_TYPE(self);
 
@@ -338,9 +342,10 @@ SHA3_get_name(SHA3object *self, void *closure)
 
 
 static PyObject *
-SHA3_get_digest_size(SHA3object *self, void *closure)
+SHA3_get_digest_size(PyObject *op, void *Py_UNUSED(closure))
 {
     // Preserving previous behavior: variable-length algorithms return 0
+    SHA3object *self = _SHA3object_CAST(op);
     if (Hacl_Hash_SHA3_is_shake(self->hash_state))
       return PyLong_FromLong(0);
     else
@@ -349,8 +354,9 @@ SHA3_get_digest_size(SHA3object *self, void *closure)
 
 
 static PyObject *
-SHA3_get_capacity_bits(SHA3object *self, void *closure)
+SHA3_get_capacity_bits(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA3object *self = _SHA3object_CAST(op);
     uint32_t rate = Hacl_Hash_SHA3_block_len(self->hash_state) * 8;
     assert(rate <= 1600);
     int capacity = 1600 - rate;
@@ -359,26 +365,27 @@ SHA3_get_capacity_bits(SHA3object *self, void *closure)
 
 
 static PyObject *
-SHA3_get_rate_bits(SHA3object *self, void *closure)
+SHA3_get_rate_bits(PyObject *op, void *Py_UNUSED(closure))
 {
+    SHA3object *self = _SHA3object_CAST(op);
     uint32_t rate = Hacl_Hash_SHA3_block_len(self->hash_state) * 8;
     return PyLong_FromLong(rate);
 }
 
 static PyObject *
-SHA3_get_suffix(SHA3object *self, void *closure)
+SHA3_get_suffix(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     unsigned char suffix[2] = {0x06, 0};
     return PyBytes_FromStringAndSize((const char *)suffix, 1);
 }
 
 static PyGetSetDef SHA3_getseters[] = {
-    {"block_size", (getter)SHA3_get_block_size, NULL, NULL, NULL},
-    {"name", (getter)SHA3_get_name, NULL, NULL, NULL},
-    {"digest_size", (getter)SHA3_get_digest_size, NULL, NULL, NULL},
-    {"_capacity_bits", (getter)SHA3_get_capacity_bits, NULL, NULL, NULL},
-    {"_rate_bits", (getter)SHA3_get_rate_bits, NULL, NULL, NULL},
-    {"_suffix", (getter)SHA3_get_suffix, NULL, NULL, NULL},
+    {"block_size", SHA3_get_block_size, NULL, NULL, NULL},
+    {"name", SHA3_get_name, NULL, NULL, NULL},
+    {"digest_size", SHA3_get_digest_size, NULL, NULL, NULL},
+    {"_capacity_bits", SHA3_get_capacity_bits, NULL, NULL, NULL},
+    {"_rate_bits", SHA3_get_rate_bits, NULL, NULL, NULL},
+    {"_suffix", SHA3_get_suffix, NULL, NULL, NULL},
     {NULL}  /* Sentinel */
 };
 
@@ -438,10 +445,11 @@ SHA3_TYPE_SLOTS(sha3_512_slots, sha3_512__doc__, SHA3_methods, SHA3_getseters);
 SHA3_TYPE_SPEC(sha3_512_spec, "sha3_512", sha3_512_slots);
 
 static PyObject *
-_SHAKE_digest(SHA3object *self, unsigned long digestlen, int hex)
+_SHAKE_digest(PyObject *op, unsigned long digestlen, int hex)
 {
     unsigned char *digest = NULL;
     PyObject *result = NULL;
+    SHA3object *self = _SHA3object_CAST(op);
 
     if (digestlen >= (1 << 29)) {
         PyErr_SetString(PyExc_ValueError, "length is too large");
@@ -483,7 +491,7 @@ static PyObject *
 _sha3_shake_128_digest_impl(SHA3object *self, unsigned long length)
 /*[clinic end generated code: output=2313605e2f87bb8f input=418ef6a36d2e6082]*/
 {
-    return _SHAKE_digest(self, length, 0);
+    return _SHAKE_digest((PyObject *)self, length, 0);
 }
 
 
@@ -500,17 +508,17 @@ static PyObject *
 _sha3_shake_128_hexdigest_impl(SHA3object *self, unsigned long length)
 /*[clinic end generated code: output=bf8e2f1e490944a8 input=69fb29b0926ae321]*/
 {
-    return _SHAKE_digest(self, length, 1);
+    return _SHAKE_digest((PyObject *)self, length, 1);
 }
 
 static PyObject *
-SHAKE_get_digest_size(SHA3object *self, void *closure)
+SHAKE_get_digest_size(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     return PyLong_FromLong(0);
 }
 
 static PyObject *
-SHAKE_get_suffix(SHA3object *self, void *closure)
+SHAKE_get_suffix(PyObject *Py_UNUSED(self), void *Py_UNUSED(closure))
 {
     unsigned char suffix[2] = {0x1f, 0};
     return PyBytes_FromStringAndSize((const char *)suffix, 1);
@@ -518,12 +526,12 @@ SHAKE_get_suffix(SHA3object *self, void *closure)
 
 
 static PyGetSetDef SHAKE_getseters[] = {
-    {"block_size", (getter)SHA3_get_block_size, NULL, NULL, NULL},
-    {"name", (getter)SHA3_get_name, NULL, NULL, NULL},
-    {"digest_size", (getter)SHAKE_get_digest_size, NULL, NULL, NULL},
-    {"_capacity_bits", (getter)SHA3_get_capacity_bits, NULL, NULL, NULL},
-    {"_rate_bits", (getter)SHA3_get_rate_bits, NULL, NULL, NULL},
-    {"_suffix", (getter)SHAKE_get_suffix, NULL, NULL, NULL},
+    {"block_size", SHA3_get_block_size, NULL, NULL, NULL},
+    {"name", SHA3_get_name, NULL, NULL, NULL},
+    {"digest_size", SHAKE_get_digest_size, NULL, NULL, NULL},
+    {"_capacity_bits", SHA3_get_capacity_bits, NULL, NULL, NULL},
+    {"_rate_bits", SHA3_get_rate_bits, NULL, NULL, NULL},
+    {"_suffix", SHAKE_get_suffix, NULL, NULL, NULL},
     {NULL}  /* Sentinel */
 };