Replace some unsafe cypclass decrefs by xdecref

Cython/Compiler/ExprNodes.py

@@ -828,8 +828,12 @@ class ExprNode(Node):
                 self.generate_subexpr_disposal_code(code)
                 self.free_subexpr_temps(code)
             if self.result() and not self.has_temp_moved:
-                code.put_decref_clear(self.result(), self.ctype(),
-                                        have_gil=not self.in_nogil_context)
+                if self.type.is_cyp_class:
+                    code.put_xdecref_clear(self.result(), self.ctype(),
+                                            have_gil=not self.in_nogil_context)
+                else:
+                    code.put_decref_clear(self.result(), self.ctype(),
+                                            have_gil=not self.in_nogil_context)
             if self.has_temp_moved:
                 code.globalstate.use_utility_code(
                     UtilityCode.load_cached("MoveIfSupported", "CppSupport.cpp"))

Cython/Compiler/Nodes.py

@@ -3735,7 +3735,7 @@ class DefNodeWrapper(FuncDefNode):
                 # The conversion from PyObject to CyObject always creates a new CyObject reference.
                 # This decrements all arguments-as-variables converted straight from an actual argument.
                 # This includes CyObjects converted directly from a corresponding PyObject argument.
-                if entry.xdecref_cleanup:
+                if entry.xdecref_cleanup or entry.type.is_cyp_class:
                     code.put_var_xdecref(entry)
                 else:
                     code.put_var_decref(entry)
@@ -3743,10 +3743,7 @@ class DefNodeWrapper(FuncDefNode):
             if entry.type.is_cyp_class:
                 # The conversion from PyObject to CyObject always creates a new CyObject reference.
                 # This decrements CyObjects converted from generic PyObject args passed via tuple and kw dict.
-                if entry.xdecref_cleanup:
-                    code.put_var_xdecref(entry)
-                else:
-                    code.put_var_decref(entry)
+                code.put_var_xdecref(entry)
 
         code.put_finish_refcount_context()
         if not self.return_type.is_void: