Rename Uninferable and instatiate_class

23 files changed, 207 insertions, 207 deletions

diff --git a/astroid/__init__.py b/astroid/__init__.py
index f67bbf9..973bb84 100644
--- a/astroid/__init__.py
+++ b/astroid/__init__.py
@@ -63,7 +63,7 @@ from astroid.bases import Instance, BoundMethod, UnboundMethod
 from astroid.node_classes import are_exclusive, unpack_infer
 from astroid.scoped_nodes import builtin_lookup
 from astroid.builder import parse
-from astroid.util import YES
+from astroid.util import Uninferable
 
 # make a manager instance (borg) accessible from astroid package
 from astroid.manager import AstroidManager
diff --git a/astroid/arguments.py b/astroid/arguments.py
index 6483189..7136834 100644
--- a/astroid/arguments.py
+++ b/astroid/arguments.py
@@ -44,11 +44,11 @@ class CallSite(object):
 
         self.positional_arguments = [
             arg for arg in self._unpacked_args
-            if arg is not util.YES
+            if arg is not util.Uninferable
         ]
         self.keyword_arguments = {
             key: value for key, value in self._unpacked_kwargs.items()
-            if value is not util.YES
+            if value is not util.Uninferable
         }
 
     @classmethod
@@ -87,29 +87,29 @@ class CallSite(object):
                 try:
                     inferred = next(value.infer(context=context))
                 except exceptions.InferenceError:
-                    values[name] = util.YES
+                    values[name] = util.Uninferable
                     continue
 
                 if not isinstance(inferred, nodes.Dict):
                     # Not something we can work with.
-                    values[name] = util.YES
+                    values[name] = util.Uninferable
                     continue
 
                 for dict_key, dict_value in inferred.items:
                     try:
                         dict_key = next(dict_key.infer(context=context))
                     except exceptions.InferenceError:
-                        values[name] = util.YES
+                        values[name] = util.Uninferable
                         continue
                     if not isinstance(dict_key, nodes.Const):
-                        values[name] = util.YES
+                        values[name] = util.Uninferable
                         continue
                     if not isinstance(dict_key.value, six.string_types):
-                        values[name] = util.YES
+                        values[name] = util.Uninferable
                         continue
                     if dict_key.value in values:
                         # The name is already in the dictionary
-                        values[dict_key.value] = util.YES
+                        values[dict_key.value] = util.Uninferable
                         self.duplicated_keywords.add(dict_key.value)
                         continue
                     values[dict_key.value] = dict_value
@@ -126,14 +126,14 @@ class CallSite(object):
                 try:
                     inferred = next(arg.value.infer(context=context))
                 except exceptions.InferenceError:
-                    values.append(util.YES)
+                    values.append(util.Uninferable)
                     continue
 
-                if inferred is util.YES:
-                    values.append(util.YES)
+                if inferred is util.Uninferable:
+                    values.append(util.Uninferable)
                     continue
                 if not hasattr(inferred, 'elts'):
-                    values.append(util.YES)
+                    values.append(util.Uninferable)
                     continue
                 values.extend(inferred.elts)
             else:
diff --git a/astroid/bases.py b/astroid/bases.py
index 15cf579..05633b8 100644
--- a/astroid/bases.py
+++ b/astroid/bases.py
@@ -53,7 +53,7 @@ def _is_property(meth):
     if PROPERTIES.intersection(meth.decoratornames()):
         return True
     stripped = {name.split(".")[-1] for name in meth.decoratornames()
-                if name is not util.YES}
+                if name is not util.Uninferable}
     return any(name in stripped for name in POSSIBLE_PROPERTIES)
 
 
@@ -89,7 +89,7 @@ def _infer_stmts(stmts, context, frame=None):
         context = contextmod.InferenceContext()
 
     for stmt in stmts:
-        if stmt is util.YES:
+        if stmt is util.Uninferable:
             yield stmt
             inferred = True
             continue
@@ -101,7 +101,7 @@ def _infer_stmts(stmts, context, frame=None):
         except exceptions.NameInferenceError:
             continue
         except exceptions.InferenceError:
-            yield util.YES
+            yield util.Uninferable
             inferred = True
     if not inferred:
         raise exceptions.InferenceError(
@@ -115,14 +115,14 @@ def _infer_method_result_truth(instance, method_name, context):
     meth = next(instance.igetattr(method_name, context=context), None)
     if meth and hasattr(meth, 'infer_call_result'):
         if not meth.callable():
-            return util.YES
+            return util.Uninferable
         for value in meth.infer_call_result(instance, context=context):
-            if value is util.YES:
+            if value is util.Uninferable:
                 return value
 
             inferred = next(value.infer(context=context))
             return inferred.bool_value()
-    return util.YES
+    return util.Uninferable
 
 
 class Instance(Proxy):
@@ -205,7 +205,7 @@ class Instance(Proxy):
         """infer what a class instance is returning when called"""
         inferred = False
         for node in self._proxied.igetattr('__call__', context):
-            if node is util.YES or not node.callable():
+            if node is util.Uninferable or not node.callable():
                 continue
             for res in node.infer_call_result(caller, context):
                 inferred = True
@@ -296,7 +296,7 @@ class UnboundMethod(Proxy):
         if (self._proxied.name == '__new__' and
                 self._proxied.parent.frame().qname() == '%s.object' % BUILTINS):
             infer = caller.args[0].infer() if caller.args else []
-            return ((x is util.YES and x or Instance(x)) for x in infer)
+            return ((x is util.Uninferable and x or Instance(x)) for x in infer)
         return self._proxied.infer_call_result(caller, context)
 
     def bool_value(self):
diff --git a/astroid/brain/brain_builtin_inference.py b/astroid/brain/brain_builtin_inference.py
index eb61b70..47ef7f3 100644
--- a/astroid/brain/brain_builtin_inference.py
+++ b/astroid/brain/brain_builtin_inference.py
@@ -120,10 +120,10 @@ def _generic_inference(node, context, node_type, transform):
             inferred = next(arg.infer(context=context))
         except (InferenceError, StopIteration):
             raise UseInferenceDefault()
-        if inferred is util.YES:
+        if inferred is util.Uninferable:
             raise UseInferenceDefault()
         transformed = transform(inferred)
-    if not transformed or transformed is util.YES:
+    if not transformed or transformed is util.Uninferable:
         raise UseInferenceDefault()
     return transformed
 
@@ -293,7 +293,7 @@ def infer_super(node, context=None):
         if scope.type == 'classmethod':
             mro_type = cls
         else:
-            mro_type = cls.instanciate_class()
+            mro_type = cls.instantiate_class()
     else:
         # TODO(cpopa): support flow control (multiple inference values).
         try:
@@ -305,7 +305,7 @@ def infer_super(node, context=None):
         except InferenceError:
             raise UseInferenceDefault
 
-    if mro_pointer is util.YES or mro_type is util.YES:
+    if mro_pointer is util.Uninferable or mro_type is util.Uninferable:
         # No way we could understand this.
         raise UseInferenceDefault
 
@@ -329,11 +329,11 @@ def _infer_getattr_args(node, context):
     except InferenceError:
         raise UseInferenceDefault
 
-    if obj is util.YES or attr is util.YES:
+    if obj is util.Uninferable or attr is util.Uninferable:
         # If one of the arguments is something we can't infer,
         # then also make the result of the getattr call something
         # which is unknown.
-        return util.YES, util.YES
+        return util.Uninferable, util.Uninferable
 
     is_string = (isinstance(attr, nodes.Const) and
                  isinstance(attr.value, six.string_types))
@@ -346,13 +346,13 @@ def _infer_getattr_args(node, context):
 def infer_getattr(node, context=None):
     """Understand getattr calls
 
-    If one of the arguments is an YES object, then the
-    result will be an YES object. Otherwise, the normal attribute
+    If one of the arguments is an Uninferable object, then the
+    result will be an Uninferable object. Otherwise, the normal attribute
     lookup will be done.
     """
     obj, attr = _infer_getattr_args(node, context)
-    if obj is util.YES or attr is util.YES or not hasattr(obj, 'igetattr'):
-        return util.YES
+    if obj is util.Uninferable or attr is util.Uninferable or not hasattr(obj, 'igetattr'):
+        return util.Uninferable
 
     try:
         return next(obj.igetattr(attr, context=context))
@@ -373,17 +373,17 @@ def infer_hasattr(node, context=None):
     This always guarantees three possible outcomes for calling
     hasattr: Const(False) when we are sure that the object
     doesn't have the intended attribute, Const(True) when
-    we know that the object has the attribute and YES
+    we know that the object has the attribute and Uninferable
     when we are unsure of the outcome of the function call.
     """
     try:
         obj, attr = _infer_getattr_args(node, context)
-        if obj is util.YES or attr is util.YES or not hasattr(obj, 'getattr'):
-            return util.YES
+        if obj is util.Uninferable or attr is util.Uninferable or not hasattr(obj, 'getattr'):
+            return util.Uninferable
         obj.getattr(attr, context=context)
     except UseInferenceDefault:
         # Can't infer something from this function call.
-        return util.YES
+        return util.Uninferable
     except AttributeInferenceError:
         # Doesn't have it.
         return nodes.Const(False)
@@ -406,9 +406,9 @@ def infer_callable(node, context=None):
     try:
         inferred = next(argument.infer(context=context))
     except InferenceError:
-        return util.YES
-    if inferred is util.YES:
-        return util.YES
+        return util.Uninferable
+    if inferred is util.Uninferable:
+        return util.Uninferable
     return nodes.Const(inferred.callable())
 
 
@@ -425,13 +425,13 @@ def infer_bool(node, context=None):
     try:
         inferred = next(argument.infer(context=context))
     except InferenceError:
-        return util.YES
-    if inferred is util.YES:
-        return util.YES
+        return util.Uninferable
+    if inferred is util.Uninferable:
+        return util.Uninferable
 
     bool_value = inferred.bool_value()
-    if bool_value is util.YES:
-        return util.YES
+    if bool_value is util.Uninferable:
+        return util.Uninferable
     return nodes.Const(bool_value)
 
 
@@ -451,7 +451,7 @@ def infer_slice(node, context=None):
 
     args = list(map(helpers.safe_infer, args))
     for arg in args:
-        if not arg or arg is util.YES:
+        if not arg or arg is util.Uninferable:
             raise UseInferenceDefault
         if not isinstance(arg, nodes.Const):
             raise UseInferenceDefault
diff --git a/astroid/brain/brain_stdlib.py b/astroid/brain/brain_stdlib.py
index a03358f..6a988d6 100644
--- a/astroid/brain/brain_stdlib.py
+++ b/astroid/brain/brain_stdlib.py
@@ -23,7 +23,7 @@ def infer_func_form(node, base_type, context=None, enum=False):
     def infer_first(node):
         try:
             value = next(node.infer(context=context))
-            if value is util.YES:
+            if value is util.Uninferable:
                 raise UseInferenceDefault()
             else:
                 return value
@@ -330,7 +330,7 @@ def infer_enum_class(node):
                 fake.parent = target.parent
                 for method in node.mymethods():
                     fake.locals[method.name] = [method]
-                new_targets.append(fake.instanciate_class())
+                new_targets.append(fake.instantiate_class())
             node.locals[local] = new_targets
         break
     return node
diff --git a/astroid/builder.py b/astroid/builder.py
index 4db4051..9e06ef7 100644
--- a/astroid/builder.py
+++ b/astroid/builder.py
@@ -227,7 +227,7 @@ class AstroidBuilder(raw_building.InspectBuilder):
         try:
             frame = node.frame()
             for inferred in node.expr.infer():
-                if inferred is util.YES:
+                if inferred is util.Uninferable:
                     continue
                 try:
                     if inferred.__class__ is bases.Instance:
diff --git a/astroid/decorators.py b/astroid/decorators.py
index 2f02962..3e9f409 100644
--- a/astroid/decorators.py
+++ b/astroid/decorators.py
@@ -123,7 +123,7 @@ def yes_if_nothing_inferred(func, instance, args, kwargs):
         inferred = True
         yield node
     if not inferred:
-        yield util.YES
+        yield util.Uninferable
 
 
 @wrapt.decorator
diff --git a/astroid/helpers.py b/astroid/helpers.py
index d4cd0dd..6d48b0d 100644
--- a/astroid/helpers.py
+++ b/astroid/helpers.py
@@ -94,9 +94,9 @@ def object_type(node, context=None):
     try:

         types = set(_object_type(node, context))

     except exceptions.InferenceError:

-        return util.YES

+        return util.Uninferable

     if len(types) > 1 or not types:

-        return util.YES

+        return util.Uninferable

     return list(types)[0]

 

 

@@ -140,7 +140,7 @@ def has_known_bases(klass, context=None):
 

 def _type_check(type1, type2):

     if not all(map(has_known_bases, (type1, type2))):

-        return util.YES

+        return util.Uninferable

 

     if not all([type1.newstyle, type2.newstyle]):

         return False

@@ -148,7 +148,7 @@ def _type_check(type1, type2):
         return type1 in type2.mro()[:-1]

     except exceptions.MroError:

         # The MRO is invalid.

-        return util.YES

+        return util.Uninferable

 

 

 def is_subtype(type1, type2):

diff --git a/astroid/inference.py b/astroid/inference.py
index fda4546..47f60d9 100644
--- a/astroid/inference.py
+++ b/astroid/inference.py
@@ -108,7 +108,7 @@ def infer_call(self, context=None):
                                                      keywords=self.keywords)
     callcontext.boundnode = None
     for callee in self.func.infer(context):
-        if callee is util.YES:
+        if callee is util.Uninferable:
             yield callee
             continue
         try:
@@ -168,7 +168,7 @@ nodes.ImportFrom._infer = infer_import_from
 def infer_attribute(self, context=None):
     """infer an Attribute node by using getattr on the associated object"""
     for owner in self.expr.infer(context):
-        if owner is util.YES:
+        if owner is util.Uninferable:
             yield owner
             continue
         try:
@@ -240,13 +240,13 @@ def infer_subscript(self, context=None):
     """
 
     value = next(self.value.infer(context))
-    if value is util.YES:
-        yield util.YES
+    if value is util.Uninferable:
+        yield util.Uninferable
         return
 
     index = next(self.slice.infer(context))
-    if index is util.YES:
-        yield util.YES
+    if index is util.Uninferable:
+        yield util.Uninferable
         return
 
     if value.__class__ == bases.Instance:
@@ -280,8 +280,8 @@ def infer_subscript(self, context=None):
 
     # Prevent inferring if the inferred subscript
     # is the same as the original subscripted object.
-    if self is assigned or assigned is util.YES:
-        yield util.YES
+    if self is assigned or assigned is util.Uninferable:
+        yield util.Uninferable
         return
     for inferred in assigned.infer(context):
         yield inferred
@@ -312,31 +312,31 @@ def _infer_boolop(self, context=None):
     try:
         values = [value.infer(context=context) for value in values]
     except exceptions.InferenceError:
-        yield util.YES
+        yield util.Uninferable
         return
 
     for pair in itertools.product(*values):
-        if any(item is util.YES for item in pair):
-            # Can't infer the final result, just yield YES.
-            yield util.YES
+        if any(item is util.Uninferable for item in pair):
+            # Can't infer the final result, just yield Uninferable.
+            yield util.Uninferable
             continue
 
         bool_values = [item.bool_value() for item in pair]
-        if any(item is util.YES for item in bool_values):
-            # Can't infer the final result, just yield YES.
-            yield util.YES
+        if any(item is util.Uninferable for item in bool_values):
+            # Can't infer the final result, just yield Uninferable.
+            yield util.Uninferable
             continue
 
         # Since the boolean operations are short circuited operations,
         # this code yields the first value for which the predicate is True
         # and if no value respected the predicate, then the last value will
-        # be returned (or YES if there was no last value).
+        # be returned (or Uninferable if there was no last value).
         # This is conforming to the semantics of `and` and `or`:
         #   1 and 0 -> 1
         #   0 and 1 -> 0
         #   1 or 0 -> 1
         #   0 or 1 -> 1
-        value = util.YES
+        value = util.Uninferable
         for value, bool_value in zip(pair, bool_values):
             if predicate(bool_value):
                 yield value
@@ -359,7 +359,7 @@ def _filter_operation_errors(self, infer_callable, context, error):
             # For the sake of .infer(), we don't care about operation
             # errors, which is the job of pylint. So return something
             # which shows that we can't infer the result.
-            yield util.YES
+            yield util.Uninferable
         else:
             yield result
 
@@ -377,12 +377,12 @@ def _infer_unaryop(self, context=None):
             if meth is None:
                 # `not node`. Determine node's boolean
                 # value and negate its result, unless it is
-                # YES, which will be returned as is.
+                # Uninferable, which will be returned as is.
                 bool_value = operand.bool_value()
-                if bool_value is not util.YES:
+                if bool_value is not util.Uninferable:
                     yield nodes.const_factory(not bool_value)
                 else:
-                    yield util.YES
+                    yield util.Uninferable
             else:
                 if not isinstance(operand, bases.Instance):
                     # The operation was used on something which
@@ -393,7 +393,7 @@ def _infer_unaryop(self, context=None):
                 try:
                     meth = operand.getattr(meth, context=context)[0]
                     inferred = next(meth.infer(context=context))
-                    if inferred is util.YES or not inferred.callable():
+                    if inferred is util.Uninferable or not inferred.callable():
                         continue
 
                     context = contextmod.copy_context(context)
@@ -409,7 +409,7 @@ def _infer_unaryop(self, context=None):
                     # The unary operation special method was not found.
                     yield util.BadUnaryOperationMessage(operand, self.op, exc)
                 except exceptions.InferenceError:
-                    yield util.YES
+                    yield util.Uninferable
 
 
 @decorators.raise_if_nothing_inferred
@@ -570,23 +570,23 @@ def _infer_binary_operation(left, right, op, context, flow_factory):
         except exceptions.AttributeInferenceError:
             continue
         except exceptions.InferenceError:
-            yield util.YES
+            yield util.Uninferable
             return
         else:
-            if any(result is util.YES for result in results):
-                yield util.YES
+            if any(result is util.Uninferable for result in results):
+                yield util.Uninferable
                 return
 
             # TODO(cpopa): since the inferrence engine might return
             # more values than are actually possible, we decide
-            # to return util.YES if we have union types.
+            # to return util.Uninferable if we have union types.
             if all(map(_is_not_implemented, results)):
                 continue
             not_implemented = sum(1 for result in results
                                   if _is_not_implemented(result))
             if not_implemented and not_implemented != len(results):
                 # Can't decide yet what this is, not yet though.
-                yield util.YES
+                yield util.Uninferable
                 return
 
             for result in results:
@@ -612,15 +612,15 @@ def _infer_binop(self, context):
     rhs_context = context.clone()
 
     for lhs in left.infer(context=lhs_context):
-        if lhs is util.YES:
+        if lhs is util.Uninferable:
             # Don't know how to process this.
-            yield util.YES
+            yield util.Uninferable
             return
 
         for rhs in right.infer(context=rhs_context):
-            if rhs is util.YES:
+            if rhs is util.Uninferable:
                 # Don't know how to process this.
-                yield util.YES
+                yield util.Uninferable
                 return
 
             results = _infer_binary_operation(lhs, rhs, op,
@@ -646,9 +646,9 @@ def _infer_augassign(self, context=None):
     op = self.op
 
     for lhs in self.target.infer_lhs(context=context):
-        if lhs is util.YES:
+        if lhs is util.Uninferable:
             # Don't know how to process this.
-            yield util.YES
+            yield util.Uninferable
             return
 
         # TODO(cpopa): if we have A() * A(), trying to infer
@@ -658,9 +658,9 @@ def _infer_augassign(self, context=None):
         rhs_context = context.clone()
         rhs_context.path = set()
         for rhs in self.value.infer(context=rhs_context):
-            if rhs is util.YES:
+            if rhs is util.Uninferable:
                 # Don't know how to process this.
-                yield util.YES
+                yield util.Uninferable
                 return
 
             results = _infer_binary_operation(lhs, rhs, op,
@@ -708,14 +708,14 @@ nodes.AssignAttr._infer = infer_assign
 @decorators.path_wrapper
 def infer_empty_node(self, context=None):
     if not self.has_underlying_object():
-        yield util.YES
+        yield util.Uninferable
     else:
         try:
             for inferred in MANAGER.infer_ast_from_something(self.object,
                                                              context=context):
                 yield inferred
         except exceptions.AstroidError:
-            yield util.YES
+            yield util.Uninferable
 nodes.EmptyNode._infer = infer_empty_node
 
 
diff --git a/astroid/manager.py b/astroid/manager.py
index c14125f..0f6673d 100644
--- a/astroid/manager.py
+++ b/astroid/manager.py
@@ -252,7 +252,7 @@ class AstroidManager(object):
                 yield inferred
         else:
             for inferred in modastroid.igetattr(name, context):
-                yield inferred.instanciate_class()
+                yield inferred.instantiate_class()
 
     def register_failed_import_hook(self, hook):
         """Registers a hook to resolve imports that cannot be found otherwise.
diff --git a/astroid/node_classes.py b/astroid/node_classes.py
index 5a92210..3dbba34 100644
--- a/astroid/node_classes.py
+++ b/astroid/node_classes.py
@@ -56,9 +56,9 @@ def unpack_infer(stmt, context=None):
     if inferred is stmt:
         yield inferred
         return
-    # else, infer recursivly, except YES object that should be returned as is
+    # else, infer recursivly, except Uninferable object that should be returned as is
     for inferred in stmt.infer(context):
-        if inferred is util.YES:
+        if inferred is util.Uninferable:
             yield inferred
         else:
             for inf_inf in unpack_infer(inferred, context):
@@ -426,8 +426,8 @@ class NodeNG(object):
                       PendingDeprecationWarning, stacklevel=2)
         return self.inferred()
 
-    def instanciate_class(self):
-        """instanciate a node if it is a ClassDef node, else return self"""
+    def instantiate_class(self):
+        """instantiate a node if it is a ClassDef node, else return self"""
         return self
 
     def has_base(self, node):
@@ -572,10 +572,10 @@ class NodeNG(object):
               method.
             * True. Most of constructs are True by default:
               classes, functions, modules etc
-            * YES: the inference engine is uncertain of the
+            * Uninferable: the inference engine is uncertain of the
               node's value.
         """
-        return util.YES
+        return util.Uninferable
 
 
 class Statement(NodeNG):
@@ -1292,7 +1292,7 @@ class Dict(NodeNG, bases.Instance):
                 except IndexError:
                     continue
             for inferredkey in key.infer(context):
-                if inferredkey is util.YES:
+                if inferredkey is util.Uninferable:
                     continue
                 if isinstance(inferredkey, Const) \
                         and inferredkey.value == lookup_key:
diff --git a/astroid/protocols.py b/astroid/protocols.py
index 5809e4a..6b6c0c0 100644
--- a/astroid/protocols.py
+++ b/astroid/protocols.py
@@ -127,12 +127,12 @@ def const_infer_binary_op(self, operator, other, context, _):
                 # ArithmeticError is not enough: float >> float is a TypeError
                 yield not_implemented
             except Exception: # pylint: disable=broad-except
-                yield util.YES
+                yield util.Uninferable
         except TypeError:
             yield not_implemented
     elif isinstance(self.value, six.string_types) and operator == '%':
         # TODO(cpopa): implement string interpolation later on.
-        yield util.YES
+        yield util.Uninferable
     else:
         yield not_implemented
 
@@ -145,7 +145,7 @@ def _multiply_seq_by_int(self, other, context):
     for elt in self.elts:
         infered = helpers.safe_infer(elt, context)
         if infered is None:
-            infered = util.YES
+            infered = util.Uninferable
         elts.append(infered)
     node.elts = elts * other.value
     return node
@@ -157,9 +157,9 @@ def tl_infer_binary_op(self, operator, other, context, method):
     if isinstance(other, self.__class__) and operator == '+':
         node = self.__class__()
         elts = [n for elt in self.elts for n in elt.infer(context)
-                if not n is util.YES]
+                if not n is util.Uninferable]
         elts += [n for elt in other.elts for n in elt.infer(context)
-                 if not n is util.YES]
+                 if not n is util.Uninferable]
         node.elts = elts
         yield node
     elif isinstance(other, nodes.Const) and operator == '*':
@@ -171,7 +171,7 @@ def tl_infer_binary_op(self, operator, other, context, method):
         # Verify if the instance supports __index__.
         as_index = helpers.class_instance_as_index(other)
         if not as_index:
-            yield util.YES
+            yield util.Uninferable
         else:
             yield _multiply_seq_by_int(self, as_index, context)
     else:
@@ -206,7 +206,7 @@ def _resolve_looppart(parts, asspath, context):
     asspath = asspath[:]
     index = asspath.pop(0)
     for part in parts:
-        if part is util.YES:
+        if part is util.Uninferable:
             continue
         # XXX handle __iter__ and log potentially detected errors
         if not hasattr(part, 'itered'):
@@ -226,7 +226,7 @@ def _resolve_looppart(parts, asspath, context):
                 # we achieved to resolved the assignment path,
                 # don't infer the last part
                 yield assigned
-            elif assigned is util.YES:
+            elif assigned is util.Uninferable:
                 break
             else:
                 # we are not yet on the last part of the path
@@ -278,7 +278,7 @@ def _arguments_infer_argname(self, name, context):
     # arguments information may be missing, in which case we can't do anything
     # more
     if not (self.args or self.vararg or self.kwarg):
-        yield util.YES
+        yield util.Uninferable
         return
     # first argument of instance/class method
     if self.args and getattr(self.args[0], 'name', None) == name:
@@ -307,15 +307,15 @@ def _arguments_infer_argname(self, name, context):
         kwarg.parent = self
         yield kwarg
         return
-    # if there is a default value, yield it. And then yield YES to reflect
+    # if there is a default value, yield it. And then yield Uninferable to reflect
     # we can't guess given argument value
     try:
         context = contextmod.copy_context(context)
         for inferred in self.default_value(name).infer(context):
             yield inferred
-        yield util.YES
+        yield util.Uninferable
     except exceptions.NoDefault:
-        yield util.YES
+        yield util.Uninferable
 
 
 def arguments_assigned_stmts(self, node, context, asspath=None):
@@ -363,7 +363,7 @@ def _resolve_asspart(parts, asspath, context):
                 # we achieved to resolved the assignment path, don't infer the
                 # last part
                 yield assigned
-            elif assigned is util.YES:
+            elif assigned is util.Uninferable:
                 return
             else:
                 # we are not yet on the last part of the path search on each
@@ -523,11 +523,11 @@ def starred_assigned_stmts(self, node=None, context=None, asspath=None):
         try:
             rhs = next(value.infer(context))
         except exceptions.InferenceError:
-            yield util.YES
+            yield util.Uninferable
             return
-        if rhs is util.YES or not hasattr(rhs, 'elts'):
+        if rhs is util.Uninferable or not hasattr(rhs, 'elts'):
             # Not interested in inferred values without elts.
-            yield util.YES
+            yield util.Uninferable
             return
 
         elts = collections.deque(rhs.elts[:])
diff --git a/astroid/scoped_nodes.py b/astroid/scoped_nodes.py
index a994392..ab130f5 100644
--- a/astroid/scoped_nodes.py
+++ b/astroid/scoped_nodes.py
@@ -552,7 +552,7 @@ class DictComp(ComprehensionScope):
             self.generators = generators
 
     def bool_value(self):
-        return util.YES
+        return util.Uninferable
 
 
 class SetComp(ComprehensionScope):
@@ -573,7 +573,7 @@ class SetComp(ComprehensionScope):
             self.generators = generators
 
     def bool_value(self):
-        return util.YES
+        return util.Uninferable
 
 
 class _ListComp(node_classes.NodeNG):
@@ -587,7 +587,7 @@ class _ListComp(node_classes.NodeNG):
         self.generators = generators
 
     def bool_value(self):
-        return util.YES
+        return util.Uninferable
 
 
 if six.PY3:
@@ -936,7 +936,7 @@ class FunctionDef(node_classes.Statement, Lambda):
                 c.hide = True
                 c.parent = self
                 class_bases = [next(b.infer(context)) for b in caller.args[1:]]
-                c.bases = [base for base in class_bases if base != util.YES]
+                c.bases = [base for base in class_bases if base != util.Uninferable]
                 c._metaclass = metaclass
                 yield c
                 return
@@ -949,7 +949,7 @@ class FunctionDef(node_classes.Statement, Lambda):
                     for inferred in returnnode.value.infer(context):
                         yield inferred
                 except exceptions.InferenceError:
-                    yield util.YES
+                    yield util.Uninferable
 
     def bool_value(self):
         return True
@@ -990,7 +990,7 @@ def _is_metaclass(klass, seen=None):
                 if isinstance(baseobj, bases.Instance):
                     # not abstract
                     return False
-                if baseobj is util.YES:
+                if baseobj is util.Uninferable:
                     continue
                 if baseobj is klass:
                     continue
@@ -1160,7 +1160,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
                 isinstance(name_node.value, six.string_types)):
             name = name_node.value
         else:
-            return util.YES
+            return util.Uninferable
 
         result = ClassDef(name, None)
 
@@ -1170,9 +1170,9 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
             result.bases = class_bases.itered()
         else:
             # There is currently no AST node that can represent an 'unknown'
-            # node (YES is not an AST node), therefore we simply return YES here
+            # node (Uninferable is not an AST node), therefore we simply return Uninferable here
             # although we know at least the name of the class.
-            return util.YES
+            return util.Uninferable
 
         # Get the members of the class
         try:
@@ -1343,7 +1343,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
         raise exceptions.AttributeInferenceError(target=self, attribute=name,
                                                  context=context)
 
-    def instanciate_class(self):
+    def instantiate_class(self):
         """return Instance of ClassDef node, else return self"""
         return bases.Instance(self)
 
@@ -1352,7 +1352,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
 
         This method doesn't look in the instance_attrs dictionary
         since it's done by an Instance proxy at inference time.  It
-        may return a YES object if the attribute has not been actually
+        may return a Uninferable object if the attribute has not been actually
         found but a __getattr__ or __getattribute__ method is defined.
         If *class_context* is given, then it's considered that the
         attribute is accessed from a class context,
@@ -1442,7 +1442,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
         try:
             for inferred in bases._infer_stmts(self.getattr(name, context),
                                                context, frame=self):
-                # yield YES object instead of descriptors when necessary
+                # yield Uninferable object instead of descriptors when necessary
                 if (not isinstance(inferred, node_classes.Const)
                         and isinstance(inferred, bases.Instance)):
                     try:
@@ -1450,13 +1450,13 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
                     except exceptions.AttributeInferenceError:
                         yield inferred
                     else:
-                        yield util.YES
+                        yield util.Uninferable
                 else:
                     yield function_to_method(inferred, self)
         except exceptions.AttributeInferenceError as error:
             if not name.startswith('__') and self.has_dynamic_getattr(context):
-                # class handle some dynamic attributes, return a YES object
-                yield util.YES
+                # class handle some dynamic attributes, return a Uninferable object
+                yield util.Uninferable
             else:
                 util.reraise(exceptions.InferenceError(
                     error.message, target=self, attribute=name, context=context))
@@ -1538,7 +1538,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
             # Expects this from Py3k TreeRebuilder
             try:
                 return next(node for node in self._metaclass.infer()
-                            if node is not util.YES)
+                            if node is not util.Uninferable)
             except (exceptions.InferenceError, StopIteration):
                 return None
         if six.PY3:
@@ -1561,7 +1561,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
             inferred = next(assignment.infer())
         except exceptions.InferenceError:
             return
-        if inferred is util.YES: # don't expose this
+        if inferred is util.Uninferable: # don't expose this
             return None
         return inferred
 
@@ -1620,7 +1620,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
                 values = [item[0] for item in slots.items]
             else:
                 values = slots.itered()
-            if values is util.YES:
+            if values is util.Uninferable:
                 continue
             if not values:
                 # Stop the iteration, because the class
@@ -1630,7 +1630,7 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
             for elt in values:
                 try:
                     for inferred in elt.infer():
-                        if inferred is util.YES:
+                        if inferred is util.Uninferable:
                             continue
                         if (not isinstance(inferred, node_classes.Const) or
                                 not isinstance(inferred.value,
diff --git a/astroid/tests/unittest_brain.py b/astroid/tests/unittest_brain.py
index ca47d52..87f4913 100644
--- a/astroid/tests/unittest_brain.py
+++ b/astroid/tests/unittest_brain.py
@@ -119,7 +119,7 @@ class NamedTupleTest(unittest.TestCase):
         def foo(fields):
            return __(namedtuple("foo", fields))
         """)
-        self.assertIs(util.YES, next(klass.infer()))
+        self.assertIs(util.Uninferable, next(klass.infer()))
 
     @unittest.skipIf(sys.version_info[0] > 2,
                      'namedtuple inference is broken on Python 3')
diff --git a/astroid/tests/unittest_builder.py b/astroid/tests/unittest_builder.py
index 485963b..dc161d0 100644
--- a/astroid/tests/unittest_builder.py
+++ b/astroid/tests/unittest_builder.py
@@ -482,7 +482,7 @@ class BuilderTest(unittest.TestCase):
         n = test_utils.get_name_node(astroid, 'n')
         self.assertIsNot(n.scope(), astroid)
         self.assertEqual([i.__class__ for i in n.infer()],
-                         [util.YES.__class__])
+                         [util.Uninferable.__class__])
 
     def test_no_future_imports(self):
         mod = builder.parse("import sys")
diff --git a/astroid/tests/unittest_helpers.py b/astroid/tests/unittest_helpers.py
index 6225966..fc95d63 100644
--- a/astroid/tests/unittest_helpers.py
+++ b/astroid/tests/unittest_helpers.py
@@ -154,7 +154,7 @@ class TestHelpers(unittest.TestCase):
         from unknown import Unknown

         u = Unknown #@

         ''')

-        self.assertEqual(helpers.object_type(node), util.YES)

+        self.assertEqual(helpers.object_type(node), util.Uninferable)

 

     def test_object_type_too_many_types(self):

         node = test_utils.extract_node('''

@@ -166,7 +166,7 @@ class TestHelpers(unittest.TestCase):
                 return 1

         test(Unknown) #@

         ''')

-        self.assertEqual(helpers.object_type(node), util.YES)

+        self.assertEqual(helpers.object_type(node), util.Uninferable)

 

     def test_is_subtype(self):

         ast_nodes = test_utils.extract_node('''

@@ -216,8 +216,8 @@ class TestHelpers(unittest.TestCase):
         class F(D, E): pass #@

         ''')

         self.assertFalse(helpers.is_subtype(cls_e, cls_f))

-        self.assertEqual(helpers.is_subtype(cls_f, cls_e), util.YES)

-        self.assertEqual(helpers.is_supertype(cls_e, cls_f), util.YES)

+        self.assertEqual(helpers.is_subtype(cls_f, cls_e), util.Uninferable)

+        self.assertEqual(helpers.is_supertype(cls_e, cls_f), util.Uninferable)

         self.assertFalse(helpers.is_supertype(cls_f, cls_e))

 

     def test_is_subtype_supertype_unknown_bases(self):

diff --git a/astroid/tests/unittest_inference.py b/astroid/tests/unittest_inference.py
index 6adaada..19b8377 100644
--- a/astroid/tests/unittest_inference.py
+++ b/astroid/tests/unittest_inference.py
@@ -312,7 +312,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         self.assertIsInstance(obj1, nodes.Const)
         self.assertEqual(obj1.value, 0)
         obj1 = next(inferred)
-        self.assertIs(obj1, util.YES, obj1)
+        self.assertIs(obj1, util.Uninferable, obj1)
         self.assertRaises(StopIteration, partial(next, inferred))
 
     def test_args_default_inference2(self):
@@ -321,13 +321,13 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         self.assertIsInstance(obj1, nodes.Const)
         self.assertEqual(obj1.value, 4)
         obj1 = next(inferred)
-        self.assertIs(obj1, util.YES, obj1)
+        self.assertIs(obj1, util.Uninferable, obj1)
         self.assertRaises(StopIteration, partial(next, inferred))
 
     def test_inference_restrictions(self):
         inferred = test_utils.get_name_node(self.ast['C']['meth1'], 'arg1').infer()
         obj1 = next(inferred)
-        self.assertIs(obj1, util.YES, obj1)
+        self.assertIs(obj1, util.Uninferable, obj1)
         self.assertRaises(StopIteration, partial(next, inferred))
 
     def test_ancestors_inference(self):
@@ -563,7 +563,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         xxx = ast['xxx']
         self.assertSetEqual({n.__class__ for n in xxx.inferred()},
-                            {nodes.Const, util.YES.__class__})
+                            {nodes.Const, util.Uninferable.__class__})
 
     def test_method_argument(self):
         code = '''
@@ -579,13 +579,13 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         arg = test_utils.get_name_node(ast['ErudiEntitySchema']['__init__'], 'e_type')
         self.assertEqual([n.__class__ for n in arg.infer()],
-                         [util.YES.__class__])
+                         [util.Uninferable.__class__])
         arg = test_utils.get_name_node(ast['ErudiEntitySchema']['__init__'], 'kwargs')
         self.assertEqual([n.__class__ for n in arg.infer()],
                          [nodes.Dict])
         arg = test_utils.get_name_node(ast['ErudiEntitySchema']['meth'], 'e_type')
         self.assertEqual([n.__class__ for n in arg.infer()],
-                         [util.YES.__class__])
+                         [util.Uninferable.__class__])
         arg = test_utils.get_name_node(ast['ErudiEntitySchema']['meth'], 'args')
         self.assertEqual([n.__class__ for n in arg.infer()],
                          [nodes.Tuple])
@@ -722,7 +722,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         for node in ast_nodes[:3]:
             self.assertRaises(InferenceError, next, node.infer())
         for node in ast_nodes[3:]:
-            self.assertEqual(next(node.infer()), util.YES)
+            self.assertEqual(next(node.infer()), util.Uninferable)
         ast_nodes = test_utils.extract_node('''
         [1, 2, 3][None] #@
         'lala'['bala'] #@
@@ -971,7 +971,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         self.assertEqual(first.value, 43)
 
         second = next(ast_nodes[1].infer())
-        self.assertEqual(second, util.YES)
+        self.assertEqual(second, util.Uninferable)
 
     def test_binary_op_other_type_using_reflected_operands(self):
         ast_nodes = test_utils.extract_node('''
@@ -982,7 +982,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         1 + A() #@
         ''')
         first = next(ast_nodes[0].infer())
-        self.assertEqual(first, util.YES)
+        self.assertEqual(first, util.Uninferable)
 
         second = next(ast_nodes[1].infer())
         self.assertIsInstance(second, nodes.Const)
@@ -996,7 +996,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         1 + A() #@
         ''')
         first = next(ast_node.infer())
-        self.assertEqual(first, util.YES)
+        self.assertEqual(first, util.Uninferable)
 
     def test_binary_op_list_mul(self):
         for code in ('a = [[]] * 2', 'a = 2 * [[]]'):
@@ -1013,10 +1013,10 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = builder.string_build('a = [1] * None\nb = [1] * "r"')
         inferred = ast['a'].inferred()
         self.assertEqual(len(inferred), 1)
-        self.assertEqual(inferred[0], util.YES)
+        self.assertEqual(inferred[0], util.Uninferable)
         inferred = ast['b'].inferred()
         self.assertEqual(len(inferred), 1)
-        self.assertEqual(inferred[0], util.YES)
+        self.assertEqual(inferred[0], util.Uninferable)
 
     def test_binary_op_list_mul_int(self):
         'test correct handling on list multiplied by int when there are more than one'
@@ -1088,7 +1088,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         callfuncnode = test_utils.extract_node(code)
         inferred = list(callfuncnode.infer())
         self.assertEqual(len(inferred), 2, inferred)
-        inferred.remove(util.YES)
+        inferred.remove(util.Uninferable)
         self.assertIsInstance(inferred[0], nodes.Const)
         self.assertIsNone(inferred[0].value)
 
@@ -1100,7 +1100,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         inferred = list(ast['f'].ilookup('a'))
         self.assertEqual(len(inferred), 1)
-        self.assertEqual(inferred[0], util.YES)
+        self.assertEqual(inferred[0], util.Uninferable)
 
     def test_nonregr_instance_attrs(self):
         """non regression for instance_attrs infinite loop : pylint / #4"""
@@ -1152,7 +1152,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         self.assertTrue(ast.absolute_import_activated(), True)
         inferred = next(test_utils.get_name_node(ast, 'import_package_subpackage_module').infer())
         # failed to import since absolute_import is activated
-        self.assertIs(inferred, util.YES)
+        self.assertIs(inferred, util.Uninferable)
 
     def test_nonregr_absolute_import(self):
         ast = resources.build_file('data/absimp/string.py', 'data.absimp.string')
@@ -1270,7 +1270,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         inferred = list(test_utils.get_name_node(ast['foo'], 'spam').infer())
         self.assertEqual(len(inferred), 1)
-        self.assertIs(inferred[0], util.YES)
+        self.assertIs(inferred[0], util.Uninferable)
 
     def test_nonregr_func_global(self):
         code = '''
@@ -1461,7 +1461,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         sub = ast['sub'].inferred()[0]
         mul = ast['mul'].inferred()[0]
-        self.assertIs(sub, util.YES)
+        self.assertIs(sub, util.Uninferable)
         self.assertIsInstance(mul, nodes.Const)
         self.assertEqual(mul.value, 42)
 
@@ -1480,7 +1480,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         sub = ast['sub'].inferred()[0]
         mul = ast['mul'].inferred()[0]
-        self.assertIs(sub, util. YES)
+        self.assertIs(sub, util. Uninferable)
         self.assertIsInstance(mul, nodes.Const)
         self.assertEqual(mul.value, 42)
 
@@ -1500,7 +1500,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ast = parse(code, __name__)
         sub = ast['sub'].inferred()[0]
         mul = ast['mul'].inferred()[0]
-        self.assertIs(sub, util.YES)
+        self.assertIs(sub, util.Uninferable)
         self.assertIsInstance(mul, nodes.List)
         self.assertIsInstance(mul.elts[0], nodes.Const)
         self.assertEqual(mul.elts[0].value, 42)
@@ -1517,12 +1517,12 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         """
         ast = parse(code, __name__)
         node = ast['c']
-        self.assertEqual(node.inferred(), [util.YES])
+        self.assertEqual(node.inferred(), [util.Uninferable])
 
     def test_infer_empty_nodes(self):
         # Should not crash when trying to infer EmptyNodes.
         node = nodes.EmptyNode()
-        self.assertEqual(node.inferred(), [util.YES])
+        self.assertEqual(node.inferred(), [util.Uninferable])
 
     def test_infinite_loop_for_decorators(self):
         # Issue https://bitbucket.org/logilab/astroid/issue/50
@@ -2016,7 +2016,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
 
     def test_unary_op_leaks_stop_iteration(self):
         node = test_utils.extract_node('+[] #@')
-        self.assertEqual(util.YES, next(node.infer()))
+        self.assertEqual(util.Uninferable, next(node.infer()))
 
     def test_unary_operands(self):
         ast_nodes = test_utils.extract_node('''
@@ -2068,7 +2068,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
 
         for bad_node in ast_nodes[6:]:
             inferred = next(bad_node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
     def test_unary_op_instance_method_not_callable(self):
         ast_node = test_utils.extract_node('''
@@ -2265,11 +2265,11 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         genexpr = next(module['genexpr'].infer())
         self.assertTrue(genexpr.bool_value())
         dict_comp = next(module['dict_comp'].infer())
-        self.assertEqual(dict_comp, util.YES)
+        self.assertEqual(dict_comp, util.Uninferable)
         set_comp = next(module['set_comp'].infer())
-        self.assertEqual(set_comp, util.YES)
+        self.assertEqual(set_comp, util.Uninferable)
         list_comp = next(module['list_comp'].infer())
-        self.assertEqual(list_comp, util.YES)
+        self.assertEqual(list_comp, util.Uninferable)
         lambda_func = next(module['lambda_func'].infer())
         self.assertTrue(lambda_func)
         unbound_method = next(module['unbound_method'].infer())
@@ -2283,13 +2283,13 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         bin_op = module['bin_op'].parent.value
         self.assertTrue(bin_op.bool_value())
         bool_op = module['bool_op'].parent.value
-        self.assertEqual(bool_op.bool_value(), util.YES)
+        self.assertEqual(bool_op.bool_value(), util.Uninferable)
         callfunc = module['callfunc'].parent.value
-        self.assertEqual(callfunc.bool_value(), util.YES)
+        self.assertEqual(callfunc.bool_value(), util.Uninferable)
         good_callfunc = next(module['good_callfunc'].infer())
         self.assertTrue(good_callfunc.bool_value())
         compare = module['compare'].parent.value
-        self.assertEqual(compare.bool_value(), util.YES)
+        self.assertEqual(compare.bool_value(), util.Uninferable)
 
     def test_bool_value_instances(self):
         instances = test_utils.extract_node('''
@@ -2322,7 +2322,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         AlwaysTrueInstance() #@
         ErrorInstance() #@
         '''.format(bool=BOOL_SPECIAL_METHOD))
-        expected = (False, True, False, True, True, util.YES, util.YES)
+        expected = (False, True, False, True, True, util.Uninferable, util.Uninferable)
         for node, expected_value in zip(instances, expected):
             inferred = next(node.infer())
             self.assertEqual(inferred.bool_value(), expected_value)
@@ -2394,7 +2394,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         A() + B() #@
         ''')
         inferred = next(node.infer())
-        self.assertEqual(inferred, util.YES)
+        self.assertEqual(inferred, util.Uninferable)
 
     def test_binop_different_types_reflected_and_normal_not_implemented(self):
         node = test_utils.extract_node('''
@@ -2405,7 +2405,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         A() + B() #@
         ''')
         inferred = next(node.infer())
-        self.assertEqual(inferred, util.YES)
+        self.assertEqual(inferred, util.Uninferable)
 
     def test_binop_subtype(self):
         node = test_utils.extract_node('''
@@ -2438,7 +2438,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         B() + A() #@
         ''')
         inferred = next(node.infer())
-        self.assertEqual(inferred, util.YES)
+        self.assertEqual(inferred, util.Uninferable)
 
     def test_binop_supertype(self):
         node = test_utils.extract_node('''
@@ -2477,7 +2477,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         A() + B() #@
         ''')
         inferred = next(node.infer())
-        self.assertEqual(inferred, util.YES)
+        self.assertEqual(inferred, util.Uninferable)
 
     def test_binop_inferrence_errors(self):
         ast_nodes = test_utils.extract_node('''
@@ -2492,7 +2492,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         A() + B() #@
         ''')
         for node in ast_nodes:
-            self.assertEqual(next(node.infer()), util.YES)
+            self.assertEqual(next(node.infer()), util.Uninferable)
 
     def test_binop_ambiguity(self):
         ast_nodes = test_utils.extract_node('''
@@ -2515,7 +2515,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         C() + A() #@
         ''')
         for node in ast_nodes:
-            self.assertEqual(next(node.infer()), util.YES)
+            self.assertEqual(next(node.infer()), util.Uninferable)
 
     def test_bin_op_supertype_more_complicated_example(self):
         ast_node = test_utils.extract_node('''
@@ -2544,7 +2544,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
             def __add__(self, other): return NotImplemented
         A() + A() #@
         ''')
-        self.assertEqual(next(ast_node.infer()), util.YES)
+        self.assertEqual(next(ast_node.infer()), util.Uninferable)
 
     def test_aug_op_same_type_aug_implemented(self):
         ast_node = test_utils.extract_node('''
@@ -2579,7 +2579,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         b = B()
         b+=A() #@
         ''')
-        self.assertEqual(next(ast_node.infer()), util.YES)
+        self.assertEqual(next(ast_node.infer()), util.Uninferable)
 
     def test_aug_op_subtype_aug_op_is_implemented(self):
         ast_node = test_utils.extract_node('''
@@ -2614,7 +2614,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         f = A()
         f += B() #@
         ''')
-        self.assertEqual(next(ast_node.infer()), util.YES)
+        self.assertEqual(next(ast_node.infer()), util.Uninferable)
 
     def test_aug_different_types_augop_implemented(self):
         ast_node = test_utils.extract_node('''
@@ -2662,7 +2662,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         a = A()
         a += B() #@
         ''')
-        self.assertEqual(next(ast_node.infer()), util.YES)
+        self.assertEqual(next(ast_node.infer()), util.Uninferable)
 
     def test_augop_supertypes_not_implemented_returned_for_all(self):
         ast_node = test_utils.extract_node('''
@@ -2674,7 +2674,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         a = A()
         a += B() #@
         ''')
-        self.assertEqual(next(ast_node.infer()), util.YES)
+        self.assertEqual(next(ast_node.infer()), util.Uninferable)
 
     def test_augop_supertypes_augop_implemented(self):
         ast_node = test_utils.extract_node('''
@@ -2746,7 +2746,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
                          [1, 2, 1, 2])
         for rest in ast_nodes[1:]:
             inferred = next(rest.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
     def test_subscript_supports__index__(self):
         ast_nodes = test_utils.extract_node('''
@@ -2915,7 +2915,7 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         A()[2:] #@
         ''')
         for node in ast_nodes:
-            self.assertEqual(next(node.infer()), util.YES)
+            self.assertEqual(next(node.infer()), util.Uninferable)
 
     def test_type__new__with_metaclass(self):
         ast_node = test_utils.extract_node('''
@@ -3158,7 +3158,7 @@ class GetattrTest(unittest.TestCase):
 
         for node in ast_nodes[4:]:
             inferred = next(node.infer())
-            self.assertEqual(inferred, util.YES, node)
+            self.assertEqual(inferred, util.Uninferable, node)
 
     def test_attrname_not_string(self):
         ast_nodes = test_utils.extract_node('''
@@ -3246,7 +3246,7 @@ class GetattrTest(unittest.TestCase):
         getattr(lambda x: x, 'f') #@
         ''')
         inferred = next(node.infer())
-        self.assertEqual(inferred, util.YES)
+        self.assertEqual(inferred, util.Uninferable)
 
 
 class HasattrTest(unittest.TestCase):
@@ -3262,7 +3262,7 @@ class HasattrTest(unittest.TestCase):
         ''')
         for node in ast_nodes:
             inferred = next(node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
     def test_attribute_is_missing(self):
         ast_nodes = test_utils.extract_node('''
@@ -3305,7 +3305,7 @@ class HasattrTest(unittest.TestCase):
         hasattr(lambda x: x, 'f') #@
         ''')
         inferred = next(node.infer())
-        self.assertEqual(inferred, util.YES)
+        self.assertEqual(inferred, util.Uninferable)
 
 
 class BoolOpTest(unittest.TestCase):
@@ -3342,7 +3342,7 @@ class BoolOpTest(unittest.TestCase):
         ''')
         for node in ast_nodes:
             inferred = next(node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
     def test_other_nodes(self):
         ast_nodes = test_utils.extract_node('''
@@ -3422,7 +3422,7 @@ class TestCallable(unittest.TestCase):
         ''')
         for node in ast_nodes:
             inferred = next(node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
     def test_not_callable(self):
         ast_nodes = test_utils.extract_node('''
@@ -3448,12 +3448,12 @@ class TestBool(unittest.TestCase):
             ('bool(True)', True),
             ('bool(False)', False),
             ('bool(None)', False),
-            ('from unknown import Unknown; __(bool(Unknown))', util.YES),
+            ('from unknown import Unknown; __(bool(Unknown))', util.Uninferable),
         ]
         for code, expected in pairs:
             node = test_utils.extract_node(code)
             inferred = next(node.infer())
-            if expected is util.YES:
+            if expected is util.Uninferable:
                 self.assertEqual(expected, inferred)
             else:
                 self.assertEqual(inferred.value, expected)
@@ -3503,7 +3503,7 @@ class TestBool(unittest.TestCase):
         '''.format(method=BOOL_SPECIAL_METHOD))
         for node in ast_nodes:
             inferred = next(node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
 
 class TestType(unittest.TestCase):
@@ -3715,7 +3715,7 @@ class ArgumentsTest(unittest.TestCase):
         ''')
         for ast_node in ast_nodes:
             inferred = next(ast_node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
     def test_fail_to_infer_args(self):
         ast_nodes = test_utils.extract_node('''
@@ -3745,7 +3745,7 @@ class ArgumentsTest(unittest.TestCase):
         ''')
         for node in ast_nodes:
             inferred = next(node.infer())
-            self.assertEqual(inferred, util.YES)
+            self.assertEqual(inferred, util.Uninferable)
 
 
 class SliceTest(unittest.TestCase):
diff --git a/astroid/tests/unittest_lookup.py b/astroid/tests/unittest_lookup.py
index 7f9c43a..c91acf7 100644
--- a/astroid/tests/unittest_lookup.py
+++ b/astroid/tests/unittest_lookup.py
@@ -172,7 +172,7 @@ class LookupTest(resources.SysPathSetup, unittest.TestCase):
         """)
         var = astroid.body[1].value
         if sys.version_info < (3, 0):
-            self.assertEqual(var.inferred(), [util.YES])
+            self.assertEqual(var.inferred(), [util.Uninferable])
         else:
             self.assertRaises(exceptions.NameInferenceError, var.inferred)
 
diff --git a/astroid/tests/unittest_nodes.py b/astroid/tests/unittest_nodes.py
index 55c7268..3677bfb 100644
--- a/astroid/tests/unittest_nodes.py
+++ b/astroid/tests/unittest_nodes.py
@@ -359,7 +359,7 @@ from ..cave import wine\n\n"""
         method of this From node will be made by unpack_infer.
         inference.infer_from will try to import this module, which will fail and
         raise a InferenceException (by mixins.do_import_module). The infer_name
-        will catch this exception and yield and YES instead.
+        will catch this exception and yield and Uninferable instead.
         '''
 
         code = '''
@@ -383,7 +383,7 @@ from ..cave import wine\n\n"""
         # present in the other version.
         self.assertIsInstance(excs[0], nodes.ClassDef)
         self.assertEqual(excs[0].name, 'PickleError')
-        self.assertIs(excs[-1], util.YES)
+        self.assertIs(excs[-1], util.Uninferable)
 
     def test_absolute_import(self):
         astroid = resources.build_file('data/absimport.py')
diff --git a/astroid/tests/unittest_protocols.py b/astroid/tests/unittest_protocols.py
index 9ba4f6a..6d6bce6 100644
--- a/astroid/tests/unittest_protocols.py
+++ b/astroid/tests/unittest_protocols.py
@@ -67,7 +67,7 @@ class ProtocolTests(unittest.TestCase):
 
         for1_starred = next(assign_stmts.nodes_of_class(Starred))
         assigned = next(for1_starred.assigned_stmts())
-        self.assertEqual(assigned, util.YES)
+        self.assertEqual(assigned, util.Uninferable)
 
     def _get_starred_stmts(self, code):
         assign_stmt = extract_node("{} #@".format(code))
@@ -108,16 +108,16 @@ class ProtocolTests(unittest.TestCase):
     @require_version(minver='3.0')
     def test_assigned_stmts_starred_yes(self):
         # Not something iterable and known
-        self._helper_starred_expected("a, *b = range(3) #@", util.YES)
+        self._helper_starred_expected("a, *b = range(3) #@", util.Uninferable)
         # Not something inferrable
-        self._helper_starred_expected("a, *b = balou() #@", util.YES)
+        self._helper_starred_expected("a, *b = balou() #@", util.Uninferable)
         # In function, unknown.
         self._helper_starred_expected("""
         def test(arg):
-            head, *tail = arg #@""", util.YES)
+            head, *tail = arg #@""", util.Uninferable)
         # These cases aren't worth supporting.
         self._helper_starred_expected(
-            "a, (*b, c), d = (1, (2, 3, 4), 5) #@", util.YES)
+            "a, (*b, c), d = (1, (2, 3, 4), 5) #@", util.Uninferable)
 
     @require_version(minver='3.0')
     def test_assign_stmts_starred_fails(self):
diff --git a/astroid/tests/unittest_regrtest.py b/astroid/tests/unittest_regrtest.py
index 3e22152..8e60e8a 100644
--- a/astroid/tests/unittest_regrtest.py
+++ b/astroid/tests/unittest_regrtest.py
@@ -251,7 +251,7 @@ def test():
 
     def test_ancestors_yes_in_bases(self):
         # Test for issue https://bitbucket.org/logilab/astroid/issue/84
-        # This used to crash astroid with a TypeError, because an YES
+        # This used to crash astroid with a TypeError, because an Uninferable
         # node was present in the bases
         node = extract_node("""
         def with_metaclass(meta, *bases):
diff --git a/astroid/tests/unittest_scoped_nodes.py b/astroid/tests/unittest_scoped_nodes.py
index 47807aa..ddfb7a2 100644
--- a/astroid/tests/unittest_scoped_nodes.py
+++ b/astroid/tests/unittest_scoped_nodes.py
@@ -1132,7 +1132,7 @@ class ClassNodeTest(ModuleLoader, unittest.TestCase):
         instance = astroid['tgts']
         # used to raise "'_Yes' object is not iterable", see
         # https://bitbucket.org/logilab/astroid/issue/17
-        self.assertEqual(list(instance.infer()), [util.YES])
+        self.assertEqual(list(instance.infer()), [util.Uninferable])
 
     def test_slots(self):
         astroid = builder.parse("""
@@ -1372,7 +1372,7 @@ class ClassNodeTest(ModuleLoader, unittest.TestCase):
         class A(object):
             pass
         ''')
-        instance = cls.instanciate_class()
+        instance = cls.instantiate_class()
         func = cls.getattr('mro')
         self.assertEqual(len(func), 1)
         self.assertRaises(AttributeInferenceError, instance.getattr, 'mro')
@@ -1395,7 +1395,7 @@ class ClassNodeTest(ModuleLoader, unittest.TestCase):
         class B(object): pass 
         ''')
         cls = module['B']
-        self.assertEqual(util.YES, next(cls.igetattr('foo')))
+        self.assertEqual(util.Uninferable, next(cls.igetattr('foo')))
 
     def test_metaclass_lookup(self):
         module = builder.parse('''
diff --git a/astroid/util.py b/astroid/util.py
index 90ea7d6..10c5415 100644
--- a/astroid/util.py
+++ b/astroid/util.py
@@ -33,10 +33,10 @@ def reraise(exception):
 
 
 @object.__new__
-class YES(object):
+class Uninferable(object):
     """Special inference object, which is returned when inference fails."""
     def __repr__(self):
-        return 'YES'
+        return 'Uninferable'
 
     def __getattribute__(self, name):
         if name == 'next':