properly catch indexing of None for all Python objects, including all optimised cases

Cython/Compiler/ExprNodes.py

@@ -2663,6 +2663,7 @@ class IndexNode(ExprNode):
                 self.base = self.base.coerce_to_pyobject(env)
                 base_type = self.base.type
             if base_type.is_pyobject:
+                self.base = self.base.as_none_safe_node("'NoneType' object is unsubscriptable")
                 if self.index.type.is_int:
                     if (not setting
                         and (base_type in (list_type, tuple_type))
@@ -2685,8 +2686,6 @@ class IndexNode(ExprNode):
                 elif is_slice and base_type in (bytes_type, str_type, unicode_type, list_type, tuple_type):
                     self.type = base_type
                 else:
-                    if base_type is dict_type:
-                        self.base = self.base.as_none_safe_node("'NoneType' object is unsubscriptable")
                     self.type = py_object_type
             else:
                 if base_type.is_ptr or base_type.is_array:

tests/run/index.pyx

@@ -21,8 +21,10 @@ def index_tuple(tuple t, int i):
     5
     >>> index_tuple((1,1,2,3,5), 100)
     Traceback (most recent call last):
-    ...
     IndexError: tuple index out of range
+    >>> index_tuple(None, 0)
+    Traceback (most recent call last):
+    TypeError: 'NoneType' object is unsubscriptable
     """
     return t[i]
 
@@ -36,8 +38,10 @@ def index_list(list L, int i):
     19
     >>> index_list([2,3,5,7,11,13,17,19], 100)
     Traceback (most recent call last):
-    ...
     IndexError: list index out of range
+    >>> index_list(None, 0)
+    Traceback (most recent call last):
+    TypeError: 'NoneType' object is unsubscriptable
     """
     return L[i]
 
@@ -59,6 +63,9 @@ def index_object(object o, int i):
     Traceback (most recent call last):
     ...
     IndexError: string index out of range
+    >>> index_object(None, 0)
+    Traceback (most recent call last):
+    TypeError: 'NoneType' object is unsubscriptable
     """
     return o[i]