Revert "Fixed #16211 -- Added comparison and negation ops to F() expressions"

This reverts commit 28abf5f0eb.

Conflicts:

	docs/releases/1.5.txt

django/db/backends/__init__.py

@@ -913,9 +913,6 @@ class BaseDatabaseOperations(object):
         can vary between backends (e.g., Oracle with %% and &) and between
         subexpression types (e.g., date expressions)
         """
-        if connector == 'NOT':
-            assert len(sub_expressions) == 1
-            return 'NOT (%s)' % sub_expressions[0]
         conn = ' %s ' % connector
         return conn.join(sub_expressions)
 

django/db/models/expressions.py

@@ -18,17 +18,6 @@ class ExpressionNode(tree.Node):
     AND = '&'
     OR = '|'
 
-    # Unary operator (needs special attention in combine_expression)
-    NOT = 'NOT'
-
-    # Comparison operators
-    EQ = '='
-    GE = '>='
-    GT = '>'
-    LE = '<='
-    LT = '<'
-    NE = '<>'
-
     def __init__(self, children=None, connector=None, negated=False):
         if children is not None and len(children) > 1 and connector is None:
             raise TypeError('You have to specify a connector.')
@@ -104,32 +93,6 @@ class ExpressionNode(tree.Node):
     def __ror__(self, other):
         return self._combine(other, self.OR, True)
 
-    def __invert__(self):
-        obj = ExpressionNode([self], connector=self.NOT, negated=True)
-        return obj
-
-    def __eq__(self, other):
-        return self._combine(other, self.EQ, False)
-
-    def __ge__(self, other):
-        return self._combine(other, self.GE, False)
-
-    def __gt__(self, other):
-        return self._combine(other, self.GT, False)
-
-    def __le__(self, other):
-        return self._combine(other, self.LE, False)
-
-    def __lt__(self, other):
-        return self._combine(other, self.LT, False)
-
-    def __ne__(self, other):
-        return self._combine(other, self.NE, False)
-
-    def __bool__(self):
-        raise TypeError('Boolean operators should be avoided. Use bitwise operators.')
-    __nonzero__ = __bool__
-
     def prepare_database_save(self, unused):
         return self
 

django/utils/tree.py

@@ -88,12 +88,8 @@ class Node(object):
         Otherwise, the whole tree is pushed down one level and a new root
         connector is created, connecting the existing tree and the new node.
         """
-        # Using for loop with 'is' instead of 'if node in children' so node
-        # __eq__ method doesn't get called. The __eq__ method can be overriden
-        # by subtypes, for example the F-expression.
-        for child in self.children:
-            if node is child and conn_type == self.connector:
-                return
+        if node in self.children and conn_type == self.connector:
+            return
         if len(self.children) < 2:
             self.connector = conn_type
         if self.connector == conn_type: