Disable bindings for staticmethods

Cython/Compiler/Nodes.py

@@ -2294,6 +2294,8 @@ class DefNode(FuncDefNode):
         if env.is_py_class_scope:
             if not self.is_staticmethod and not self.is_classmethod:
                 rhs.binding = True
+            else:
+                rhs.binding = False
 
         self.assmt = SingleAssignmentNode(self.pos,
             lhs = ExprNodes.NameNode(self.pos, name = self.name),

tests/run/staticmethod.pyx

@@ -25,3 +25,21 @@ class class4:
     @staticmethod
     def plus1(a):
         return a + 1
+
+def nested_class():
+    """
+    >>> cls = nested_class()
+    >>> cls.plus1(1)
+    2
+    >>> obj = cls()
+    >>> obj.plus1(1)
+    2
+    """
+    class class5(object):
+        def __new__(cls): # implicit staticmethod
+            return object.__new__(cls)
+
+        @staticmethod
+        def plus1(a):
+            return a + 1
+    return class5