bpo-34762: Update PyContext* to PyObject* in asyncio and decimal (GH-9609)

This fixes various compiler warnings.

Modules/_asynciomodule.c

@@ -61,7 +61,7 @@ typedef enum {
     PyObject_HEAD                                                           \
     PyObject *prefix##_loop;                                                \
     PyObject *prefix##_callback0;                                           \
-    PyContext *prefix##_context0;                                           \
+    PyObject *prefix##_context0;                                            \
     PyObject *prefix##_callbacks;                                           \
     PyObject *prefix##_exception;                                           \
     PyObject *prefix##_result;                                              \
@@ -81,7 +81,7 @@ typedef struct {
     PyObject *task_fut_waiter;
     PyObject *task_coro;
     PyObject *task_name;
-    PyContext *task_context;
+    PyObject *task_context;
     int task_must_cancel;
     int task_log_destroy_pending;
 } TaskObj;
@@ -340,7 +340,7 @@ get_event_loop(void)
 
 
 static int
-call_soon(PyObject *loop, PyObject *func, PyObject *arg, PyContext *ctx)
+call_soon(PyObject *loop, PyObject *func, PyObject *arg, PyObject *ctx)
 {
     PyObject *handle;
     PyObject *stack[3];
@@ -451,7 +451,7 @@ future_schedule_callbacks(FutureObj *fut)
         PyObject *cb = PyTuple_GET_ITEM(cb_tup, 0);
         PyObject *ctx = PyTuple_GET_ITEM(cb_tup, 1);
 
-        if (call_soon(fut->fut_loop, cb, (PyObject *)fut, (PyContext *)ctx)) {
+        if (call_soon(fut->fut_loop, cb, (PyObject *)fut, ctx)) {
             /* If an error occurs in pure-Python implementation,
                all callbacks are cleared. */
             Py_CLEAR(fut->fut_callbacks);
@@ -619,7 +619,7 @@ future_get_result(FutureObj *fut, PyObject **result)
 }
 
 static PyObject *
-future_add_done_callback(FutureObj *fut, PyObject *arg, PyContext *ctx)
+future_add_done_callback(FutureObj *fut, PyObject *arg, PyObject *ctx)
 {
     if (!future_is_alive(fut)) {
         PyErr_SetString(PyExc_RuntimeError, "uninitialized Future object");
@@ -906,16 +906,15 @@ _asyncio_Future_add_done_callback_impl(FutureObj *self, PyObject *fn,
 /*[clinic end generated code: output=7ce635bbc9554c1e input=15ab0693a96e9533]*/
 {
     if (context == NULL) {
-        context = (PyObject *)PyContext_CopyCurrent();
+        context = PyContext_CopyCurrent();
         if (context == NULL) {
             return NULL;
         }
-        PyObject *res = future_add_done_callback(
-            self, fn, (PyContext *)context);
+        PyObject *res = future_add_done_callback(self, fn, context);
         Py_DECREF(context);
         return res;
     }
-    return future_add_done_callback(self, fn, (PyContext *)context);
+    return future_add_done_callback(self, fn, context);
 }
 
 /*[clinic input]

Modules/_decimal/_decimal.c

@@ -122,7 +122,7 @@ incr_false(void)
 }
 
 
-static PyContextVar *current_context_var;
+static PyObject *current_context_var;
 
 /* Template for creating new thread contexts, calling Context() without
  * arguments and initializing the module_context on first access. */
@@ -1500,7 +1500,7 @@ init_current_context(void)
     }
     CTX(tl_context)->status = 0;
 
-    PyContextToken *tok = PyContextVar_Set(current_context_var, tl_context);
+    PyObject *tok = PyContextVar_Set(current_context_var, tl_context);
     if (tok == NULL) {
         Py_DECREF(tl_context);
         return NULL;
@@ -1561,7 +1561,7 @@ PyDec_SetCurrentContext(PyObject *self UNUSED, PyObject *v)
         Py_INCREF(v);
     }
 
-    PyContextToken *tok = PyContextVar_Set(current_context_var, v);
+    PyObject *tok = PyContextVar_Set(current_context_var, v);
     Py_DECREF(v);
     if (tok == NULL) {
         return NULL;