From 45e1b49415003790b1b9b20cf02bbee8488357b9 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Wed, 21 Feb 2018 10:58:54 +0200
Subject: [PATCH 1/6] bpo-32892: Use ast.Constant instead of specific constant
 AST types.

---
 Doc/library/ast.rst                           |   8 +-
 Doc/whatsnew/3.8.rst                          |   5 +
 Include/Python-ast.h                          |  36 +-
 Lib/ast.py                                    |  84 ++++-
 Lib/inspect.py                                |  10 +-
 Lib/test/test_ast.py                          | 118 ++++---
 Lib/test/test_fstring.py                      |  24 +-
 .../2018-09-20-17-35-05.bpo-32892.TOUBdg.rst  |   4 +
 Parser/Python.asdl                            |  12 +-
 Parser/asdl_c.py                              |  39 +--
 Python/Python-ast.c                           | 312 +-----------------
 Python/ast.c                                  |  82 ++---
 Python/ast_opt.c                              |  61 +---
 Python/ast_unparse.c                          |  18 +-
 Python/compile.c                              |  64 +---
 Python/symtable.c                             |   5 -
 Tools/clinic/clinic.py                        |  14 +-
 Tools/parser/unparse.py                       |  23 +-
 18 files changed, 245 insertions(+), 674 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst

diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index 9ff422cdf503cb..a727dd6a6fbca9 100644
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -78,8 +78,8 @@ Node classes
 
       node = ast.UnaryOp()
       node.op = ast.USub()
-      node.operand = ast.Num()
-      node.operand.n = 5
+      node.operand = ast.Constant()
+      node.operand.value = 5
       node.operand.lineno = 0
       node.operand.col_offset = 0
       node.lineno = 0
@@ -87,7 +87,7 @@ Node classes
 
    or the more compact ::
 
-      node = ast.UnaryOp(ast.USub(), ast.Num(5, lineno=0, col_offset=0),
+      node = ast.UnaryOp(ast.USub(), ast.Constant(5, lineno=0, col_offset=0),
                          lineno=0, col_offset=0)
 
 
@@ -239,7 +239,7 @@ and classes for traversing abstract syntax trees:
           def visit_Name(self, node):
               return copy_location(Subscript(
                   value=Name(id='data', ctx=Load()),
-                  slice=Index(value=Str(s=node.id)),
+                  slice=Index(value=Constant(value=node.id)),
                   ctx=node.ctx
               ), node)
 
diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
index 1c129a704429f2..357de3cfb99e31 100644
--- a/Doc/whatsnew/3.8.rst
+++ b/Doc/whatsnew/3.8.rst
@@ -216,6 +216,11 @@ Deprecated
 
   (Contributed by Berker Peksag in :issue:`9372`.)
 
+* :mod:`ast` classes ``Num``, ``Str``, ``Bytes``, ``NameConstant`` and
+  ``Ellipsis`` are considered deprecated and will be removed in future Python
+  versions. :class:`~ast.Constant` should be used instead.
+  (Contributed by Serhiy Storchaka in :issue:`32892`.)
+
 
 Removed
 =======
diff --git a/Include/Python-ast.h b/Include/Python-ast.h
index 8e0f750a8250b0..2913d1d2d0a96b 100644
--- a/Include/Python-ast.h
+++ b/Include/Python-ast.h
@@ -208,11 +208,10 @@ enum _expr_kind {BoolOp_kind=1, BinOp_kind=2, UnaryOp_kind=3, Lambda_kind=4,
                   IfExp_kind=5, Dict_kind=6, Set_kind=7, ListComp_kind=8,
                   SetComp_kind=9, DictComp_kind=10, GeneratorExp_kind=11,
                   Await_kind=12, Yield_kind=13, YieldFrom_kind=14,
-                  Compare_kind=15, Call_kind=16, Num_kind=17, Str_kind=18,
-                  FormattedValue_kind=19, JoinedStr_kind=20, Bytes_kind=21,
-                  NameConstant_kind=22, Ellipsis_kind=23, Constant_kind=24,
-                  Attribute_kind=25, Subscript_kind=26, Starred_kind=27,
-                  Name_kind=28, List_kind=29, Tuple_kind=30};
+                  Compare_kind=15, Call_kind=16, FormattedValue_kind=17,
+                  JoinedStr_kind=18, Constant_kind=19, Attribute_kind=20,
+                  Subscript_kind=21, Starred_kind=22, Name_kind=23,
+                  List_kind=24, Tuple_kind=25};
 struct _expr {
     enum _expr_kind kind;
     union {
@@ -297,14 +296,6 @@ struct _expr {
             asdl_seq *keywords;
         } Call;
 
-        struct {
-            object n;
-        } Num;
-
-        struct {
-            string s;
-        } Str;
-
         struct {
             expr_ty value;
             int conversion;
@@ -315,14 +306,6 @@ struct _expr {
             asdl_seq *values;
         } JoinedStr;
 
-        struct {
-            bytes s;
-        } Bytes;
-
-        struct {
-            singleton value;
-        } NameConstant;
-
         struct {
             constant value;
         } Constant;
@@ -566,23 +549,12 @@ expr_ty _Py_Compare(expr_ty left, asdl_int_seq * ops, asdl_seq * comparators,
 #define Call(a0, a1, a2, a3, a4, a5) _Py_Call(a0, a1, a2, a3, a4, a5)
 expr_ty _Py_Call(expr_ty func, asdl_seq * args, asdl_seq * keywords, int
                  lineno, int col_offset, PyArena *arena);
-#define Num(a0, a1, a2, a3) _Py_Num(a0, a1, a2, a3)
-expr_ty _Py_Num(object n, int lineno, int col_offset, PyArena *arena);
-#define Str(a0, a1, a2, a3) _Py_Str(a0, a1, a2, a3)
-expr_ty _Py_Str(string s, int lineno, int col_offset, PyArena *arena);
 #define FormattedValue(a0, a1, a2, a3, a4, a5) _Py_FormattedValue(a0, a1, a2, a3, a4, a5)
 expr_ty _Py_FormattedValue(expr_ty value, int conversion, expr_ty format_spec,
                            int lineno, int col_offset, PyArena *arena);
 #define JoinedStr(a0, a1, a2, a3) _Py_JoinedStr(a0, a1, a2, a3)
 expr_ty _Py_JoinedStr(asdl_seq * values, int lineno, int col_offset, PyArena
                       *arena);
-#define Bytes(a0, a1, a2, a3) _Py_Bytes(a0, a1, a2, a3)
-expr_ty _Py_Bytes(bytes s, int lineno, int col_offset, PyArena *arena);
-#define NameConstant(a0, a1, a2, a3) _Py_NameConstant(a0, a1, a2, a3)
-expr_ty _Py_NameConstant(singleton value, int lineno, int col_offset, PyArena
-                         *arena);
-#define Ellipsis(a0, a1, a2) _Py_Ellipsis(a0, a1, a2)
-expr_ty _Py_Ellipsis(int lineno, int col_offset, PyArena *arena);
 #define Constant(a0, a1, a2, a3) _Py_Constant(a0, a1, a2, a3)
 expr_ty _Py_Constant(constant value, int lineno, int col_offset, PyArena
                      *arena);
diff --git a/Lib/ast.py b/Lib/ast.py
index bfe346bba8e3d7..fab19fbdf3c578 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -48,10 +48,8 @@ def literal_eval(node_or_string):
         node_or_string = node_or_string.body
     def _convert_num(node):
         if isinstance(node, Constant):
-            if isinstance(node.value, (int, float, complex)):
+            if type(node.value) in (int, float, complex):
                 return node.value
-        elif isinstance(node, Num):
-            return node.n
         raise ValueError('malformed node or string: ' + repr(node))
     def _convert_signed_num(node):
         if isinstance(node, UnaryOp) and isinstance(node.op, (UAdd, USub)):
@@ -64,10 +62,6 @@ def _convert_signed_num(node):
     def _convert(node):
         if isinstance(node, Constant):
             return node.value
-        elif isinstance(node, (Str, Bytes)):
-            return node.s
-        elif isinstance(node, Num):
-            return node.n
         elif isinstance(node, Tuple):
             return tuple(map(_convert, node.elts))
         elif isinstance(node, List):
@@ -77,8 +71,6 @@ def _convert(node):
         elif isinstance(node, Dict):
             return dict(zip(map(_convert, node.keys),
                             map(_convert, node.values)))
-        elif isinstance(node, NameConstant):
-            return node.value
         elif isinstance(node, BinOp) and isinstance(node.op, (Add, Sub)):
             left = _convert_signed_num(node.left)
             right = _convert_num(node.right)
@@ -329,3 +321,77 @@ def generic_visit(self, node):
                 else:
                     setattr(node, field, new_node)
         return node
+
+
+def _getter(self):
+    return self.value
+
+def _setter(self, value):
+    self.value = value
+
+Constant.n = property(_getter, _setter)
+Constant.s = property(_getter, _setter)
+
+_unspecified = object()
+
+
+class Num(Constant):
+    _fields = ('n',)
+
+    def __new__(cls, s=_unspecified, **kwargs):
+        if s is _unspecified:
+            return Constant(**kwargs)
+        return Constant(value=s, **kwargs)
+
+    @staticmethod
+    def __instancecheck__(instance):
+        return (isinstance(instance, Constant) and
+                type(instance.value) in (int, float, complex))
+
+
+class Str(Constant):
+    _fields = ('s',)
+
+    def __new__(cls, s=_unspecified, **kwargs):
+        if s is _unspecified:
+            return Constant(**kwargs)
+        return Constant(value=s, **kwargs)
+
+    @staticmethod
+    def __instancecheck__(instance):
+        return isinstance(instance, Constant) and type(instance.value) is str
+
+
+class Bytes(Constant):
+    _fields = ('s',)
+
+    def __new__(cls, s=_unspecified, **kwargs):
+        if s is _unspecified:
+            return Constant(**kwargs)
+        return Constant(value=s, **kwargs)
+
+    @staticmethod
+    def __instancecheck__(instance):
+        return isinstance(instance, Constant) and type(instance.value) is bytes
+
+
+class NameConstant(Constant):
+    def __new__(cls, *args, **kwargs):
+        return Constant(*args, **kwargs)
+
+    @staticmethod
+    def __instancecheck__(instance):
+        return (isinstance(instance, Constant) and
+                (instance.value is False or instance.value is True or
+                 instance.value is None))
+
+
+class Ellipsis(Constant):
+    _fields = ()
+
+    def __new__(cls, **kwargs):
+        return Constant(..., **kwargs)
+
+    @staticmethod
+    def __instancecheck__(instance):
+        return isinstance(instance, Constant) and instance.value is ...
diff --git a/Lib/inspect.py b/Lib/inspect.py
index e799a83a74046f..5b7f526939b60f 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -2005,14 +2005,8 @@ def wrap_value(s):
             except NameError:
                 raise RuntimeError()
 
-        if isinstance(value, str):
-            return ast.Str(value)
-        if isinstance(value, (int, float)):
-            return ast.Num(value)
-        if isinstance(value, bytes):
-            return ast.Bytes(value)
-        if value in (True, False, None):
-            return ast.NameConstant(value)
+        if isinstance(value, (str, int, float, bytes, bool, type(None))):
+            return ast.Constant(value)
         raise RuntimeError()
 
     class RewriteSymbolics(ast.NodeTransformer):
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 72f8467847e8dc..7bfb31a56263cb 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -300,12 +300,16 @@ def test_field_attr_writable(self):
 
     def test_classattrs(self):
         x = ast.Num()
-        self.assertEqual(x._fields, ('n',))
+        self.assertEqual(x._fields, ('value',))
+
+        with self.assertRaises(AttributeError):
+            x.value
 
         with self.assertRaises(AttributeError):
             x.n
 
         x = ast.Num(42)
+        self.assertEqual(x.value, 42)
         self.assertEqual(x.n, 42)
 
         with self.assertRaises(AttributeError):
@@ -319,7 +323,8 @@ def test_classattrs(self):
 
         x = ast.Num(42, lineno=0)
         self.assertEqual(x.lineno, 0)
-        self.assertEqual(x._fields, ('n',))
+        self.assertEqual(x._fields, ('value',))
+        self.assertEqual(x.value, 42)
         self.assertEqual(x.n, 42)
 
         self.assertRaises(TypeError, ast.Num, 1, 2)
@@ -446,17 +451,17 @@ def test_dump(self):
         node = ast.parse('spam(eggs, "and cheese")')
         self.assertEqual(ast.dump(node),
             "Module(body=[Expr(value=Call(func=Name(id='spam', ctx=Load()), "
-            "args=[Name(id='eggs', ctx=Load()), Str(s='and cheese')], "
+            "args=[Name(id='eggs', ctx=Load()), Constant(value='and cheese')], "
             "keywords=[]))])"
         )
         self.assertEqual(ast.dump(node, annotate_fields=False),
             "Module([Expr(Call(Name('spam', Load()), [Name('eggs', Load()), "
-            "Str('and cheese')], []))])"
+            "Constant('and cheese')], []))])"
         )
         self.assertEqual(ast.dump(node, include_attributes=True),
             "Module(body=[Expr(value=Call(func=Name(id='spam', ctx=Load(), "
             "lineno=1, col_offset=0), args=[Name(id='eggs', ctx=Load(), "
-            "lineno=1, col_offset=5), Str(s='and cheese', lineno=1, "
+            "lineno=1, col_offset=5), Constant(value='and cheese', lineno=1, "
             "col_offset=11)], keywords=[], "
             "lineno=1, col_offset=0), lineno=1, col_offset=0)])"
         )
@@ -465,8 +470,8 @@ def test_copy_location(self):
         src = ast.parse('1 + 1', mode='eval')
         src.body.right = ast.copy_location(ast.Num(2), src.body.right)
         self.assertEqual(ast.dump(src, include_attributes=True),
-            'Expression(body=BinOp(left=Num(n=1, lineno=1, col_offset=0), '
-            'op=Add(), right=Num(n=2, lineno=1, col_offset=4), lineno=1, '
+            'Expression(body=BinOp(left=Constant(value=1, lineno=1, col_offset=0), '
+            'op=Add(), right=Constant(value=2, lineno=1, col_offset=4), lineno=1, '
             'col_offset=0))'
         )
 
@@ -477,11 +482,11 @@ def test_fix_missing_locations(self):
         self.assertEqual(src, ast.fix_missing_locations(src))
         self.assertEqual(ast.dump(src, include_attributes=True),
             "Module(body=[Expr(value=Call(func=Name(id='write', ctx=Load(), "
-            "lineno=1, col_offset=0), args=[Str(s='spam', lineno=1, "
+            "lineno=1, col_offset=0), args=[Constant(value='spam', lineno=1, "
             "col_offset=6)], keywords=[], "
             "lineno=1, col_offset=0), lineno=1, col_offset=0), "
             "Expr(value=Call(func=Name(id='spam', ctx=Load(), lineno=1, "
-            "col_offset=0), args=[Str(s='eggs', lineno=1, col_offset=0)], "
+            "col_offset=0), args=[Constant(value='eggs', lineno=1, col_offset=0)], "
             "keywords=[], lineno=1, "
             "col_offset=0), lineno=1, col_offset=0)])"
         )
@@ -490,16 +495,16 @@ def test_increment_lineno(self):
         src = ast.parse('1 + 1', mode='eval')
         self.assertEqual(ast.increment_lineno(src, n=3), src)
         self.assertEqual(ast.dump(src, include_attributes=True),
-            'Expression(body=BinOp(left=Num(n=1, lineno=4, col_offset=0), '
-            'op=Add(), right=Num(n=1, lineno=4, col_offset=4), lineno=4, '
+            'Expression(body=BinOp(left=Constant(value=1, lineno=4, col_offset=0), '
+            'op=Add(), right=Constant(value=1, lineno=4, col_offset=4), lineno=4, '
             'col_offset=0))'
         )
         # issue10869: do not increment lineno of root twice
         src = ast.parse('1 + 1', mode='eval')
         self.assertEqual(ast.increment_lineno(src.body, n=3), src.body)
         self.assertEqual(ast.dump(src, include_attributes=True),
-            'Expression(body=BinOp(left=Num(n=1, lineno=4, col_offset=0), '
-            'op=Add(), right=Num(n=1, lineno=4, col_offset=4), lineno=4, '
+            'Expression(body=BinOp(left=Constant(value=1, lineno=4, col_offset=0), '
+            'op=Add(), right=Constant(value=1, lineno=4, col_offset=4), lineno=4, '
             'col_offset=0))'
         )
 
@@ -514,10 +519,10 @@ def test_iter_child_nodes(self):
         self.assertEqual(len(list(ast.iter_child_nodes(node.body))), 4)
         iterator = ast.iter_child_nodes(node.body)
         self.assertEqual(next(iterator).id, 'spam')
-        self.assertEqual(next(iterator).n, 23)
-        self.assertEqual(next(iterator).n, 42)
+        self.assertEqual(next(iterator).value, 23)
+        self.assertEqual(next(iterator).value, 42)
         self.assertEqual(ast.dump(next(iterator)),
-            "keyword(arg='eggs', value=Str(s='leek'))"
+            "keyword(arg='eggs', value=Constant(value='leek'))"
         )
 
     def test_get_docstring(self):
@@ -627,10 +632,13 @@ class ASTValidatorTests(unittest.TestCase):
     def mod(self, mod, msg=None, mode="exec", *, exc=ValueError):
         mod.lineno = mod.col_offset = 0
         ast.fix_missing_locations(mod)
-        with self.assertRaises(exc) as cm:
+        if msg is None:
             compile(mod, "<test>", mode)
-        if msg is not None:
-            self.assertIn(msg, str(cm.exception))
+        else:
+            with self.assertRaises(exc) as cm:
+                compile(mod, "<test>", mode)
+            if msg is not None:
+                self.assertIn(msg, str(cm.exception))
 
     def expr(self, node, msg=None, *, exc=ValueError):
         mod = ast.Module([ast.Expr(node)])
@@ -927,9 +935,9 @@ def test_compare(self):
         comp = ast.Compare(left, [ast.In()], [ast.Num(4), ast.Num(5)])
         self.expr(comp, "different number of comparators and operands")
         comp = ast.Compare(ast.Num("blah"), [ast.In()], [left])
-        self.expr(comp, "non-numeric", exc=TypeError)
+        self.expr(comp)
         comp = ast.Compare(left, [ast.In()], [ast.Num("blah")])
-        self.expr(comp, "non-numeric", exc=TypeError)
+        self.expr(comp)
 
     def test_call(self):
         func = ast.Name("x", ast.Load())
@@ -950,8 +958,10 @@ class subfloat(float):
             pass
         class subcomplex(complex):
             pass
-        for obj in "0", "hello", subint(), subfloat(), subcomplex():
-            self.expr(ast.Num(obj), "non-numeric", exc=TypeError)
+        for obj in "0", "hello":
+            self.expr(ast.Num(obj))
+        for obj in subint(), subfloat(), subcomplex():
+            self.expr(ast.Num(obj), "invalid type", exc=TypeError)
 
     def test_attribute(self):
         attr = ast.Attribute(ast.Name("x", ast.Store()), "y", ast.Load())
@@ -993,7 +1003,7 @@ def test_tuple(self):
         self._sequence(ast.Tuple)
 
     def test_nameconstant(self):
-        self.expr(ast.NameConstant(4), "singleton must be True, False, or None")
+        self.expr(ast.NameConstant(4))
 
     def test_stdlib_validates(self):
         stdlib = os.path.dirname(ast.__file__)
@@ -1140,35 +1150,35 @@ def main():
 
 #### EVERYTHING BELOW IS GENERATED #####
 exec_results = [
-('Module', [('Expr', (1, 0), ('NameConstant', (1, 0), None))]),
-('Module', [('Expr', (1, 0), ('Str', (1, 0), 'module docstring'))]),
+('Module', [('Expr', (1, 0), ('Constant', (1, 0), None))]),
+('Module', [('Expr', (1, 0), ('Constant', (1, 0), 'module docstring'))]),
 ('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Pass', (1, 9))], [], None)]),
-('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (1, 9), ('Str', (1, 9), 'function docstring'))], [], None)]),
+('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (1, 9), ('Constant', (1, 9), 'function docstring'))], [], None)]),
 ('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [('arg', (1, 6), 'a', None)], None, [], [], None, []), [('Pass', (1, 10))], [], None)]),
-('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [('arg', (1, 6), 'a', None)], None, [], [], None, [('Num', (1, 8), 0)]), [('Pass', (1, 12))], [], None)]),
+('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [('arg', (1, 6), 'a', None)], None, [], [], None, [('Constant', (1, 8), 0)]), [('Pass', (1, 12))], [], None)]),
 ('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], ('arg', (1, 7), 'args', None), [], [], None, []), [('Pass', (1, 14))], [], None)]),
 ('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], ('arg', (1, 8), 'kwargs', None), []), [('Pass', (1, 17))], [], None)]),
-('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [('arg', (1, 6), 'a', None), ('arg', (1, 9), 'b', None), ('arg', (1, 14), 'c', None), ('arg', (1, 22), 'd', None), ('arg', (1, 28), 'e', None)], ('arg', (1, 35), 'args', None), [('arg', (1, 41), 'f', None)], [('Num', (1, 43), 42)], ('arg', (1, 49), 'kwargs', None), [('Num', (1, 11), 1), ('NameConstant', (1, 16), None), ('List', (1, 24), [], ('Load',)), ('Dict', (1, 30), [], [])]), [('Expr', (1, 58), ('Str', (1, 58), 'doc for f()'))], [], None)]),
+('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [('arg', (1, 6), 'a', None), ('arg', (1, 9), 'b', None), ('arg', (1, 14), 'c', None), ('arg', (1, 22), 'd', None), ('arg', (1, 28), 'e', None)], ('arg', (1, 35), 'args', None), [('arg', (1, 41), 'f', None)], [('Constant', (1, 43), 42)], ('arg', (1, 49), 'kwargs', None), [('Constant', (1, 11), 1), ('Constant', (1, 16), None), ('List', (1, 24), [], ('Load',)), ('Dict', (1, 30), [], [])]), [('Expr', (1, 58), ('Constant', (1, 58), 'doc for f()'))], [], None)]),
 ('Module', [('ClassDef', (1, 0), 'C', [], [], [('Pass', (1, 8))], [])]),
-('Module', [('ClassDef', (1, 0), 'C', [], [], [('Expr', (1, 9), ('Str', (1, 9), 'docstring for class C'))], [])]),
+('Module', [('ClassDef', (1, 0), 'C', [], [], [('Expr', (1, 9), ('Constant', (1, 9), 'docstring for class C'))], [])]),
 ('Module', [('ClassDef', (1, 0), 'C', [('Name', (1, 8), 'object', ('Load',))], [], [('Pass', (1, 17))], [])]),
-('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Return', (1, 8), ('Num', (1, 15), 1))], [], None)]),
+('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Return', (1, 8), ('Constant', (1, 15), 1))], [], None)]),
 ('Module', [('Delete', (1, 0), [('Name', (1, 4), 'v', ('Del',))])]),
-('Module', [('Assign', (1, 0), [('Name', (1, 0), 'v', ('Store',))], ('Num', (1, 4), 1))]),
-('Module', [('AugAssign', (1, 0), ('Name', (1, 0), 'v', ('Store',)), ('Add',), ('Num', (1, 5), 1))]),
+('Module', [('Assign', (1, 0), [('Name', (1, 0), 'v', ('Store',))], ('Constant', (1, 4), 1))]),
+('Module', [('AugAssign', (1, 0), ('Name', (1, 0), 'v', ('Store',)), ('Add',), ('Constant', (1, 5), 1))]),
 ('Module', [('For', (1, 0), ('Name', (1, 4), 'v', ('Store',)), ('Name', (1, 9), 'v', ('Load',)), [('Pass', (1, 11))], [])]),
 ('Module', [('While', (1, 0), ('Name', (1, 6), 'v', ('Load',)), [('Pass', (1, 8))], [])]),
 ('Module', [('If', (1, 0), ('Name', (1, 3), 'v', ('Load',)), [('Pass', (1, 5))], [])]),
 ('Module', [('With', (1, 0), [('withitem', ('Name', (1, 5), 'x', ('Load',)), ('Name', (1, 10), 'y', ('Store',)))], [('Pass', (1, 13))])]),
 ('Module', [('With', (1, 0), [('withitem', ('Name', (1, 5), 'x', ('Load',)), ('Name', (1, 10), 'y', ('Store',))), ('withitem', ('Name', (1, 13), 'z', ('Load',)), ('Name', (1, 18), 'q', ('Store',)))], [('Pass', (1, 21))])]),
-('Module', [('Raise', (1, 0), ('Call', (1, 6), ('Name', (1, 6), 'Exception', ('Load',)), [('Str', (1, 16), 'string')], []), None)]),
+('Module', [('Raise', (1, 0), ('Call', (1, 6), ('Name', (1, 6), 'Exception', ('Load',)), [('Constant', (1, 16), 'string')], []), None)]),
 ('Module', [('Try', (1, 0), [('Pass', (2, 2))], [('ExceptHandler', (3, 0), ('Name', (3, 7), 'Exception', ('Load',)), None, [('Pass', (4, 2))])], [], [])]),
 ('Module', [('Try', (1, 0), [('Pass', (2, 2))], [], [], [('Pass', (4, 2))])]),
 ('Module', [('Assert', (1, 0), ('Name', (1, 7), 'v', ('Load',)), None)]),
 ('Module', [('Import', (1, 0), [('alias', 'sys', None)])]),
 ('Module', [('ImportFrom', (1, 0), 'sys', [('alias', 'v', None)], 0)]),
 ('Module', [('Global', (1, 0), ['v'])]),
-('Module', [('Expr', (1, 0), ('Num', (1, 0), 1))]),
+('Module', [('Expr', (1, 0), ('Constant', (1, 0), 1))]),
 ('Module', [('Pass', (1, 0))]),
 ('Module', [('For', (1, 0), ('Name', (1, 4), 'v', ('Store',)), ('Name', (1, 9), 'v', ('Load',)), [('Break', (1, 11))], [])]),
 ('Module', [('For', (1, 0), ('Name', (1, 4), 'v', ('Store',)), ('Name', (1, 9), 'v', ('Load',)), [('Continue', (1, 11))], [])]),
@@ -1181,40 +1191,40 @@ def main():
 ('Module', [('Expr', (1, 0), ('DictComp', (1, 0), ('Name', (1, 1), 'a', ('Load',)), ('Name', (1, 5), 'b', ('Load',)), [('comprehension', ('Tuple', (1, 11), [('Name', (1, 11), 'v', ('Store',)), ('Name', (1, 13), 'w', ('Store',))], ('Store',)), ('Name', (1, 18), 'x', ('Load',)), [], 0)]))]),
 ('Module', [('Expr', (1, 0), ('SetComp', (1, 0), ('Name', (1, 1), 'r', ('Load',)), [('comprehension', ('Name', (1, 7), 'l', ('Store',)), ('Name', (1, 12), 'x', ('Load',)), [('Name', (1, 17), 'g', ('Load',))], 0)]))]),
 ('Module', [('Expr', (1, 0), ('SetComp', (1, 0), ('Name', (1, 1), 'r', ('Load',)), [('comprehension', ('Tuple', (1, 7), [('Name', (1, 7), 'l', ('Store',)), ('Name', (1, 9), 'm', ('Store',))], ('Store',)), ('Name', (1, 14), 'x', ('Load',)), [], 0)]))]),
-('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('Str', (2, 1), 'async function')), ('Expr', (3, 1), ('Await', (3, 1), ('Call', (3, 7), ('Name', (3, 7), 'something', ('Load',)), [], [])))], [], None)]),
-('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('AsyncFor', (2, 1), ('Name', (2, 11), 'e', ('Store',)), ('Name', (2, 16), 'i', ('Load',)), [('Expr', (2, 19), ('Num', (2, 19), 1))], [('Expr', (3, 7), ('Num', (3, 7), 2))])], [], None)]),
-('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('AsyncWith', (2, 1), [('withitem', ('Name', (2, 12), 'a', ('Load',)), ('Name', (2, 17), 'b', ('Store',)))], [('Expr', (2, 20), ('Num', (2, 20), 1))])], [], None)]),
-('Module', [('Expr', (1, 0), ('Dict', (1, 0), [None, ('Num', (1, 10), 2)], [('Dict', (1, 3), [('Num', (1, 4), 1)], [('Num', (1, 6), 2)]), ('Num', (1, 12), 3)]))]),
-('Module', [('Expr', (1, 0), ('Set', (1, 0), [('Starred', (1, 1), ('Set', (1, 2), [('Num', (1, 3), 1), ('Num', (1, 6), 2)]), ('Load',)), ('Num', (1, 10), 3)]))]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('Constant', (2, 1), 'async function')), ('Expr', (3, 1), ('Await', (3, 1), ('Call', (3, 7), ('Name', (3, 7), 'something', ('Load',)), [], [])))], [], None)]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('AsyncFor', (2, 1), ('Name', (2, 11), 'e', ('Store',)), ('Name', (2, 16), 'i', ('Load',)), [('Expr', (2, 19), ('Constant', (2, 19), 1))], [('Expr', (3, 7), ('Constant', (3, 7), 2))])], [], None)]),
+('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('AsyncWith', (2, 1), [('withitem', ('Name', (2, 12), 'a', ('Load',)), ('Name', (2, 17), 'b', ('Store',)))], [('Expr', (2, 20), ('Constant', (2, 20), 1))])], [], None)]),
+('Module', [('Expr', (1, 0), ('Dict', (1, 0), [None, ('Constant', (1, 10), 2)], [('Dict', (1, 3), [('Constant', (1, 4), 1)], [('Constant', (1, 6), 2)]), ('Constant', (1, 12), 3)]))]),
+('Module', [('Expr', (1, 0), ('Set', (1, 0), [('Starred', (1, 1), ('Set', (1, 2), [('Constant', (1, 3), 1), ('Constant', (1, 6), 2)]), ('Load',)), ('Constant', (1, 10), 3)]))]),
 ('Module', [('AsyncFunctionDef', (1, 0), 'f', ('arguments', [], None, [], [], None, []), [('Expr', (2, 1), ('ListComp', (2, 2), ('Name', (2, 2), 'i', ('Load',)), [('comprehension', ('Name', (2, 14), 'b', ('Store',)), ('Name', (2, 19), 'c', ('Load',)), [], 1)]))], [], None)]),
 ]
 single_results = [
-('Interactive', [('Expr', (1, 0), ('BinOp', (1, 0), ('Num', (1, 0), 1), ('Add',), ('Num', (1, 2), 2)))]),
+('Interactive', [('Expr', (1, 0), ('BinOp', (1, 0), ('Constant', (1, 0), 1), ('Add',), ('Constant', (1, 2), 2)))]),
 ]
 eval_results = [
-('Expression', ('NameConstant', (1, 0), None)),
+('Expression', ('Constant', (1, 0), None)),
 ('Expression', ('BoolOp', (1, 0), ('And',), [('Name', (1, 0), 'a', ('Load',)), ('Name', (1, 6), 'b', ('Load',))])),
 ('Expression', ('BinOp', (1, 0), ('Name', (1, 0), 'a', ('Load',)), ('Add',), ('Name', (1, 4), 'b', ('Load',)))),
 ('Expression', ('UnaryOp', (1, 0), ('Not',), ('Name', (1, 4), 'v', ('Load',)))),
-('Expression', ('Lambda', (1, 0), ('arguments', [], None, [], [], None, []), ('NameConstant', (1, 7), None))),
-('Expression', ('Dict', (1, 0), [('Num', (1, 2), 1)], [('Num', (1, 4), 2)])),
+('Expression', ('Lambda', (1, 0), ('arguments', [], None, [], [], None, []), ('Constant', (1, 7), None))),
+('Expression', ('Dict', (1, 0), [('Constant', (1, 2), 1)], [('Constant', (1, 4), 2)])),
 ('Expression', ('Dict', (1, 0), [], [])),
-('Expression', ('Set', (1, 0), [('NameConstant', (1, 1), None)])),
-('Expression', ('Dict', (1, 0), [('Num', (2, 6), 1)], [('Num', (4, 10), 2)])),
+('Expression', ('Set', (1, 0), [('Constant', (1, 1), None)])),
+('Expression', ('Dict', (1, 0), [('Constant', (2, 6), 1)], [('Constant', (4, 10), 2)])),
 ('Expression', ('ListComp', (1, 1), ('Name', (1, 1), 'a', ('Load',)), [('comprehension', ('Name', (1, 7), 'b', ('Store',)), ('Name', (1, 12), 'c', ('Load',)), [('Name', (1, 17), 'd', ('Load',))], 0)])),
 ('Expression', ('GeneratorExp', (1, 1), ('Name', (1, 1), 'a', ('Load',)), [('comprehension', ('Name', (1, 7), 'b', ('Store',)), ('Name', (1, 12), 'c', ('Load',)), [('Name', (1, 17), 'd', ('Load',))], 0)])),
-('Expression', ('Compare', (1, 0), ('Num', (1, 0), 1), [('Lt',), ('Lt',)], [('Num', (1, 4), 2), ('Num', (1, 8), 3)])),
-('Expression', ('Call', (1, 0), ('Name', (1, 0), 'f', ('Load',)), [('Num', (1, 2), 1), ('Num', (1, 4), 2), ('Starred', (1, 10), ('Name', (1, 11), 'd', ('Load',)), ('Load',))], [('keyword', 'c', ('Num', (1, 8), 3)), ('keyword', None, ('Name', (1, 15), 'e', ('Load',)))])),
-('Expression', ('Num', (1, 0), 10)),
-('Expression', ('Str', (1, 0), 'string')),
+('Expression', ('Compare', (1, 0), ('Constant', (1, 0), 1), [('Lt',), ('Lt',)], [('Constant', (1, 4), 2), ('Constant', (1, 8), 3)])),
+('Expression', ('Call', (1, 0), ('Name', (1, 0), 'f', ('Load',)), [('Constant', (1, 2), 1), ('Constant', (1, 4), 2), ('Starred', (1, 10), ('Name', (1, 11), 'd', ('Load',)), ('Load',))], [('keyword', 'c', ('Constant', (1, 8), 3)), ('keyword', None, ('Name', (1, 15), 'e', ('Load',)))])),
+('Expression', ('Constant', (1, 0), 10)),
+('Expression', ('Constant', (1, 0), 'string')),
 ('Expression', ('Attribute', (1, 0), ('Name', (1, 0), 'a', ('Load',)), 'b', ('Load',))),
 ('Expression', ('Subscript', (1, 0), ('Name', (1, 0), 'a', ('Load',)), ('Slice', ('Name', (1, 2), 'b', ('Load',)), ('Name', (1, 4), 'c', ('Load',)), None), ('Load',))),
 ('Expression', ('Name', (1, 0), 'v', ('Load',))),
-('Expression', ('List', (1, 0), [('Num', (1, 1), 1), ('Num', (1, 3), 2), ('Num', (1, 5), 3)], ('Load',))),
+('Expression', ('List', (1, 0), [('Constant', (1, 1), 1), ('Constant', (1, 3), 2), ('Constant', (1, 5), 3)], ('Load',))),
 ('Expression', ('List', (1, 0), [], ('Load',))),
-('Expression', ('Tuple', (1, 0), [('Num', (1, 0), 1), ('Num', (1, 2), 2), ('Num', (1, 4), 3)], ('Load',))),
-('Expression', ('Tuple', (1, 1), [('Num', (1, 1), 1), ('Num', (1, 3), 2), ('Num', (1, 5), 3)], ('Load',))),
+('Expression', ('Tuple', (1, 0), [('Constant', (1, 0), 1), ('Constant', (1, 2), 2), ('Constant', (1, 4), 3)], ('Load',))),
+('Expression', ('Tuple', (1, 1), [('Constant', (1, 1), 1), ('Constant', (1, 3), 2), ('Constant', (1, 5), 3)], ('Load',))),
 ('Expression', ('Tuple', (1, 0), [], ('Load',))),
-('Expression', ('Call', (1, 0), ('Attribute', (1, 0), ('Attribute', (1, 0), ('Attribute', (1, 0), ('Name', (1, 0), 'a', ('Load',)), 'b', ('Load',)), 'c', ('Load',)), 'd', ('Load',)), [('Subscript', (1, 8), ('Attribute', (1, 8), ('Name', (1, 8), 'a', ('Load',)), 'b', ('Load',)), ('Slice', ('Num', (1, 12), 1), ('Num', (1, 14), 2), None), ('Load',))], [])),
+('Expression', ('Call', (1, 0), ('Attribute', (1, 0), ('Attribute', (1, 0), ('Attribute', (1, 0), ('Name', (1, 0), 'a', ('Load',)), 'b', ('Load',)), 'c', ('Load',)), 'd', ('Load',)), [('Subscript', (1, 8), ('Attribute', (1, 8), ('Name', (1, 8), 'a', ('Load',)), 'b', ('Load',)), ('Slice', ('Constant', (1, 12), 1), ('Constant', (1, 14), 2), None), ('Load',))], [])),
 ]
 main()
diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py
index 5e7efe25e39ccc..fec72e008e5bc7 100644
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@@ -116,9 +116,11 @@ def test_ast_line_numbers_multiple_formattedvalues(self):
         self.assertEqual(type(t.body[1]), ast.Expr)
         self.assertEqual(type(t.body[1].value), ast.JoinedStr)
         self.assertEqual(len(t.body[1].value.values), 4)
-        self.assertEqual(type(t.body[1].value.values[0]), ast.Str)
+        self.assertEqual(type(t.body[1].value.values[0]), ast.Constant)
+        self.assertEqual(type(t.body[1].value.values[0].value), str)
         self.assertEqual(type(t.body[1].value.values[1]), ast.FormattedValue)
-        self.assertEqual(type(t.body[1].value.values[2]), ast.Str)
+        self.assertEqual(type(t.body[1].value.values[2]), ast.Constant)
+        self.assertEqual(type(t.body[1].value.values[2].value), str)
         self.assertEqual(type(t.body[1].value.values[3]), ast.FormattedValue)
         self.assertEqual(t.body[1].lineno, 3)
         self.assertEqual(t.body[1].value.lineno, 3)
@@ -183,9 +185,11 @@ def test_ast_line_numbers_nested(self):
         self.assertEqual(binop.right.col_offset, 7)
         # check the nested call location
         self.assertEqual(len(binop.right.values), 3)
-        self.assertEqual(type(binop.right.values[0]), ast.Str)
+        self.assertEqual(type(binop.right.values[0]), ast.Constant)
+        self.assertEqual(type(binop.right.values[0].value), str)
         self.assertEqual(type(binop.right.values[1]), ast.FormattedValue)
-        self.assertEqual(type(binop.right.values[2]), ast.Str)
+        self.assertEqual(type(binop.right.values[2]), ast.Constant)
+        self.assertEqual(type(binop.right.values[2].value), str)
         self.assertEqual(binop.right.values[0].lineno, 3)
         self.assertEqual(binop.right.values[1].lineno, 3)
         self.assertEqual(binop.right.values[2].lineno, 3)
@@ -215,9 +219,11 @@ def test_ast_line_numbers_duplicate_expression(self):
         self.assertEqual(type(t.body[1].value), ast.JoinedStr)
         self.assertEqual(len(t.body[1].value.values), 5)
         self.assertEqual(type(t.body[1].value.values[0]), ast.FormattedValue)
-        self.assertEqual(type(t.body[1].value.values[1]), ast.Str)
+        self.assertEqual(type(t.body[1].value.values[1]), ast.Constant)
+        self.assertEqual(type(t.body[1].value.values[1].value), str)
         self.assertEqual(type(t.body[1].value.values[2]), ast.FormattedValue)
-        self.assertEqual(type(t.body[1].value.values[3]), ast.Str)
+        self.assertEqual(type(t.body[1].value.values[3]), ast.Constant)
+        self.assertEqual(type(t.body[1].value.values[3].value), str)
         self.assertEqual(type(t.body[1].value.values[4]), ast.FormattedValue)
         self.assertEqual(t.body[1].lineno, 3)
         self.assertEqual(t.body[1].value.lineno, 3)
@@ -287,9 +293,11 @@ def test_ast_line_numbers_multiline_fstring(self):
         self.assertEqual(type(t.body[1]), ast.Expr)
         self.assertEqual(type(t.body[1].value), ast.JoinedStr)
         self.assertEqual(len(t.body[1].value.values), 3)
-        self.assertEqual(type(t.body[1].value.values[0]), ast.Str)
+        self.assertEqual(type(t.body[1].value.values[0]), ast.Constant)
+        self.assertEqual(type(t.body[1].value.values[0].value), str)
         self.assertEqual(type(t.body[1].value.values[1]), ast.FormattedValue)
-        self.assertEqual(type(t.body[1].value.values[2]), ast.Str)
+        self.assertEqual(type(t.body[1].value.values[2]), ast.Constant)
+        self.assertEqual(type(t.body[1].value.values[2].value), str)
         # NOTE: the following invalid behavior is described in bpo-16806.
         # - line number should be the *first* line (3), not the *last* (8)
         # - column offset should not be -1
diff --git a/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst b/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst
new file mode 100644
index 00000000000000..74fafb44b6da84
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst
@@ -0,0 +1,4 @@
+The parser now represents all constants as :class:`ast.Constant` instead of
+using specific constant AST types (``Num``, ``Str``,``Bytes``,
+``NameConstant`` and ``Ellipsis``). These classes are considered deprecated
+and will be removed in future Python versions.
diff --git a/Parser/Python.asdl b/Parser/Python.asdl
index f470ad13b6551e..eee982be1c9545 100644
--- a/Parser/Python.asdl
+++ b/Parser/Python.asdl
@@ -1,8 +1,5 @@
--- ASDL's 7 builtin types are:
--- identifier, int, string, bytes, object, singleton, constant
---
--- singleton: None, True or False
--- constant can be None, whereas None means "no value" for object.
+-- ASDL's 5 builtin types are:
+-- identifier, int, string, object, constant
 
 module Python
 {
@@ -75,13 +72,8 @@ module Python
          -- x < 4 < 3 and (x < 4) < 3
          | Compare(expr left, cmpop* ops, expr* comparators)
          | Call(expr func, expr* args, keyword* keywords)
-         | Num(object n) -- a number as a PyObject.
-         | Str(string s) -- need to specify raw, unicode, etc?
          | FormattedValue(expr value, int? conversion, expr? format_spec)
          | JoinedStr(expr* values)
-         | Bytes(bytes s)
-         | NameConstant(singleton value)
-         | Ellipsis
          | Constant(constant value)
 
          -- the following expression can appear in assignment context
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index 44e3d40c615539..4c280a96c30e7e 100644
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -855,17 +855,6 @@ def visitModule(self, mod):
 
 /* Conversion Python -> AST */
 
-static int obj2ast_singleton(PyObject *obj, PyObject** out, PyArena* arena)
-{
-    if (obj != Py_None && obj != Py_True && obj != Py_False) {
-        PyErr_SetString(PyExc_ValueError,
-                        "AST singleton must be True, False, or None");
-        return 1;
-    }
-    *out = obj;
-    return 0;
-}
-
 static int obj2ast_object(PyObject* obj, PyObject** out, PyArena* arena)
 {
     if (obj == Py_None)
@@ -883,13 +872,11 @@ def visitModule(self, mod):
 
 static int obj2ast_constant(PyObject* obj, PyObject** out, PyArena* arena)
 {
-    if (obj) {
-        if (PyArena_AddPyObject(arena, obj) < 0) {
-            *out = NULL;
-            return -1;
-        }
-        Py_INCREF(obj);
+    if (PyArena_AddPyObject(arena, obj) < 0) {
+        *out = NULL;
+        return -1;
     }
+    Py_INCREF(obj);
     *out = obj;
     return 0;
 }
@@ -903,24 +890,6 @@ def visitModule(self, mod):
     return obj2ast_object(obj, out, arena);
 }
 
-static int obj2ast_string(PyObject* obj, PyObject** out, PyArena* arena)
-{
-    if (!PyUnicode_CheckExact(obj) && !PyBytes_CheckExact(obj)) {
-        PyErr_SetString(PyExc_TypeError, "AST string must be of type str");
-        return 1;
-    }
-    return obj2ast_object(obj, out, arena);
-}
-
-static int obj2ast_bytes(PyObject* obj, PyObject** out, PyArena* arena)
-{
-    if (!PyBytes_CheckExact(obj)) {
-        PyErr_SetString(PyExc_TypeError, "AST bytes must be of type bytes");
-        return 1;
-    }
-    return obj2ast_object(obj, out, arena);
-}
-
 static int obj2ast_int(PyObject* obj, int* out, PyArena* arena)
 {
     int i;
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 6a2f28e0e712d5..bbe8e69fdd504c 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -284,16 +284,6 @@ static char *Call_fields[]={
     "args",
     "keywords",
 };
-static PyTypeObject *Num_type;
-_Py_IDENTIFIER(n);
-static char *Num_fields[]={
-    "n",
-};
-static PyTypeObject *Str_type;
-_Py_IDENTIFIER(s);
-static char *Str_fields[]={
-    "s",
-};
 static PyTypeObject *FormattedValue_type;
 _Py_IDENTIFIER(conversion);
 _Py_IDENTIFIER(format_spec);
@@ -306,15 +296,6 @@ static PyTypeObject *JoinedStr_type;
 static char *JoinedStr_fields[]={
     "values",
 };
-static PyTypeObject *Bytes_type;
-static char *Bytes_fields[]={
-    "s",
-};
-static PyTypeObject *NameConstant_type;
-static char *NameConstant_fields[]={
-    "value",
-};
-static PyTypeObject *Ellipsis_type;
 static PyTypeObject *Constant_type;
 static char *Constant_fields[]={
     "value",
@@ -736,17 +717,6 @@ static PyObject* ast2obj_int(long b)
 
 /* Conversion Python -> AST */
 
-static int obj2ast_singleton(PyObject *obj, PyObject** out, PyArena* arena)
-{
-    if (obj != Py_None && obj != Py_True && obj != Py_False) {
-        PyErr_SetString(PyExc_ValueError,
-                        "AST singleton must be True, False, or None");
-        return 1;
-    }
-    *out = obj;
-    return 0;
-}
-
 static int obj2ast_object(PyObject* obj, PyObject** out, PyArena* arena)
 {
     if (obj == Py_None)
@@ -764,13 +734,11 @@ static int obj2ast_object(PyObject* obj, PyObject** out, PyArena* arena)
 
 static int obj2ast_constant(PyObject* obj, PyObject** out, PyArena* arena)
 {
-    if (obj) {
-        if (PyArena_AddPyObject(arena, obj) < 0) {
-            *out = NULL;
-            return -1;
-        }
-        Py_INCREF(obj);
+    if (PyArena_AddPyObject(arena, obj) < 0) {
+        *out = NULL;
+        return -1;
     }
+    Py_INCREF(obj);
     *out = obj;
     return 0;
 }
@@ -784,24 +752,6 @@ static int obj2ast_identifier(PyObject* obj, PyObject** out, PyArena* arena)
     return obj2ast_object(obj, out, arena);
 }
 
-static int obj2ast_string(PyObject* obj, PyObject** out, PyArena* arena)
-{
-    if (!PyUnicode_CheckExact(obj) && !PyBytes_CheckExact(obj)) {
-        PyErr_SetString(PyExc_TypeError, "AST string must be of type str");
-        return 1;
-    }
-    return obj2ast_object(obj, out, arena);
-}
-
-static int obj2ast_bytes(PyObject* obj, PyObject** out, PyArena* arena)
-{
-    if (!PyBytes_CheckExact(obj)) {
-        PyErr_SetString(PyExc_TypeError, "AST bytes must be of type bytes");
-        return 1;
-    }
-    return obj2ast_object(obj, out, arena);
-}
-
 static int obj2ast_int(PyObject* obj, int* out, PyArena* arena)
 {
     int i;
@@ -943,22 +893,11 @@ static int init_types(void)
     if (!Compare_type) return 0;
     Call_type = make_type("Call", expr_type, Call_fields, 3);
     if (!Call_type) return 0;
-    Num_type = make_type("Num", expr_type, Num_fields, 1);
-    if (!Num_type) return 0;
-    Str_type = make_type("Str", expr_type, Str_fields, 1);
-    if (!Str_type) return 0;
     FormattedValue_type = make_type("FormattedValue", expr_type,
                                     FormattedValue_fields, 3);
     if (!FormattedValue_type) return 0;
     JoinedStr_type = make_type("JoinedStr", expr_type, JoinedStr_fields, 1);
     if (!JoinedStr_type) return 0;
-    Bytes_type = make_type("Bytes", expr_type, Bytes_fields, 1);
-    if (!Bytes_type) return 0;
-    NameConstant_type = make_type("NameConstant", expr_type,
-                                  NameConstant_fields, 1);
-    if (!NameConstant_type) return 0;
-    Ellipsis_type = make_type("Ellipsis", expr_type, NULL, 0);
-    if (!Ellipsis_type) return 0;
     Constant_type = make_type("Constant", expr_type, Constant_fields, 1);
     if (!Constant_type) return 0;
     Attribute_type = make_type("Attribute", expr_type, Attribute_fields, 3);
@@ -2089,44 +2028,6 @@ Call(expr_ty func, asdl_seq * args, asdl_seq * keywords, int lineno, int
     return p;
 }
 
-expr_ty
-Num(object n, int lineno, int col_offset, PyArena *arena)
-{
-    expr_ty p;
-    if (!n) {
-        PyErr_SetString(PyExc_ValueError,
-                        "field n is required for Num");
-        return NULL;
-    }
-    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
-    if (!p)
-        return NULL;
-    p->kind = Num_kind;
-    p->v.Num.n = n;
-    p->lineno = lineno;
-    p->col_offset = col_offset;
-    return p;
-}
-
-expr_ty
-Str(string s, int lineno, int col_offset, PyArena *arena)
-{
-    expr_ty p;
-    if (!s) {
-        PyErr_SetString(PyExc_ValueError,
-                        "field s is required for Str");
-        return NULL;
-    }
-    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
-    if (!p)
-        return NULL;
-    p->kind = Str_kind;
-    p->v.Str.s = s;
-    p->lineno = lineno;
-    p->col_offset = col_offset;
-    return p;
-}
-
 expr_ty
 FormattedValue(expr_ty value, int conversion, expr_ty format_spec, int lineno,
                int col_offset, PyArena *arena)
@@ -2163,57 +2064,6 @@ JoinedStr(asdl_seq * values, int lineno, int col_offset, PyArena *arena)
     return p;
 }
 
-expr_ty
-Bytes(bytes s, int lineno, int col_offset, PyArena *arena)
-{
-    expr_ty p;
-    if (!s) {
-        PyErr_SetString(PyExc_ValueError,
-                        "field s is required for Bytes");
-        return NULL;
-    }
-    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
-    if (!p)
-        return NULL;
-    p->kind = Bytes_kind;
-    p->v.Bytes.s = s;
-    p->lineno = lineno;
-    p->col_offset = col_offset;
-    return p;
-}
-
-expr_ty
-NameConstant(singleton value, int lineno, int col_offset, PyArena *arena)
-{
-    expr_ty p;
-    if (!value) {
-        PyErr_SetString(PyExc_ValueError,
-                        "field value is required for NameConstant");
-        return NULL;
-    }
-    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
-    if (!p)
-        return NULL;
-    p->kind = NameConstant_kind;
-    p->v.NameConstant.value = value;
-    p->lineno = lineno;
-    p->col_offset = col_offset;
-    return p;
-}
-
-expr_ty
-Ellipsis(int lineno, int col_offset, PyArena *arena)
-{
-    expr_ty p;
-    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
-    if (!p)
-        return NULL;
-    p->kind = Ellipsis_kind;
-    p->lineno = lineno;
-    p->col_offset = col_offset;
-    return p;
-}
-
 expr_ty
 Constant(constant value, int lineno, int col_offset, PyArena *arena)
 {
@@ -3289,24 +3139,6 @@ ast2obj_expr(void* _o)
             goto failed;
         Py_DECREF(value);
         break;
-    case Num_kind:
-        result = PyType_GenericNew(Num_type, NULL, NULL);
-        if (!result) goto failed;
-        value = ast2obj_object(o->v.Num.n);
-        if (!value) goto failed;
-        if (_PyObject_SetAttrId(result, &PyId_n, value) == -1)
-            goto failed;
-        Py_DECREF(value);
-        break;
-    case Str_kind:
-        result = PyType_GenericNew(Str_type, NULL, NULL);
-        if (!result) goto failed;
-        value = ast2obj_string(o->v.Str.s);
-        if (!value) goto failed;
-        if (_PyObject_SetAttrId(result, &PyId_s, value) == -1)
-            goto failed;
-        Py_DECREF(value);
-        break;
     case FormattedValue_kind:
         result = PyType_GenericNew(FormattedValue_type, NULL, NULL);
         if (!result) goto failed;
@@ -3335,28 +3167,6 @@ ast2obj_expr(void* _o)
             goto failed;
         Py_DECREF(value);
         break;
-    case Bytes_kind:
-        result = PyType_GenericNew(Bytes_type, NULL, NULL);
-        if (!result) goto failed;
-        value = ast2obj_bytes(o->v.Bytes.s);
-        if (!value) goto failed;
-        if (_PyObject_SetAttrId(result, &PyId_s, value) == -1)
-            goto failed;
-        Py_DECREF(value);
-        break;
-    case NameConstant_kind:
-        result = PyType_GenericNew(NameConstant_type, NULL, NULL);
-        if (!result) goto failed;
-        value = ast2obj_singleton(o->v.NameConstant.value);
-        if (!value) goto failed;
-        if (_PyObject_SetAttrId(result, &PyId_value, value) == -1)
-            goto failed;
-        Py_DECREF(value);
-        break;
-    case Ellipsis_kind:
-        result = PyType_GenericNew(Ellipsis_type, NULL, NULL);
-        if (!result) goto failed;
-        break;
     case Constant_kind:
         result = PyType_GenericNew(Constant_type, NULL, NULL);
         if (!result) goto failed;
@@ -6606,54 +6416,6 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
         if (*out == NULL) goto failed;
         return 0;
     }
-    isinstance = PyObject_IsInstance(obj, (PyObject*)Num_type);
-    if (isinstance == -1) {
-        return 1;
-    }
-    if (isinstance) {
-        object n;
-
-        if (_PyObject_LookupAttrId(obj, &PyId_n, &tmp) < 0) {
-            return 1;
-        }
-        if (tmp == NULL) {
-            PyErr_SetString(PyExc_TypeError, "required field \"n\" missing from Num");
-            return 1;
-        }
-        else {
-            int res;
-            res = obj2ast_object(tmp, &n, arena);
-            if (res != 0) goto failed;
-            Py_CLEAR(tmp);
-        }
-        *out = Num(n, lineno, col_offset, arena);
-        if (*out == NULL) goto failed;
-        return 0;
-    }
-    isinstance = PyObject_IsInstance(obj, (PyObject*)Str_type);
-    if (isinstance == -1) {
-        return 1;
-    }
-    if (isinstance) {
-        string s;
-
-        if (_PyObject_LookupAttrId(obj, &PyId_s, &tmp) < 0) {
-            return 1;
-        }
-        if (tmp == NULL) {
-            PyErr_SetString(PyExc_TypeError, "required field \"s\" missing from Str");
-            return 1;
-        }
-        else {
-            int res;
-            res = obj2ast_string(tmp, &s, arena);
-            if (res != 0) goto failed;
-            Py_CLEAR(tmp);
-        }
-        *out = Str(s, lineno, col_offset, arena);
-        if (*out == NULL) goto failed;
-        return 0;
-    }
     isinstance = PyObject_IsInstance(obj, (PyObject*)FormattedValue_type);
     if (isinstance == -1) {
         return 1;
@@ -6748,64 +6510,6 @@ obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
         if (*out == NULL) goto failed;
         return 0;
     }
-    isinstance = PyObject_IsInstance(obj, (PyObject*)Bytes_type);
-    if (isinstance == -1) {
-        return 1;
-    }
-    if (isinstance) {
-        bytes s;
-
-        if (_PyObject_LookupAttrId(obj, &PyId_s, &tmp) < 0) {
-            return 1;
-        }
-        if (tmp == NULL) {
-            PyErr_SetString(PyExc_TypeError, "required field \"s\" missing from Bytes");
-            return 1;
-        }
-        else {
-            int res;
-            res = obj2ast_bytes(tmp, &s, arena);
-            if (res != 0) goto failed;
-            Py_CLEAR(tmp);
-        }
-        *out = Bytes(s, lineno, col_offset, arena);
-        if (*out == NULL) goto failed;
-        return 0;
-    }
-    isinstance = PyObject_IsInstance(obj, (PyObject*)NameConstant_type);
-    if (isinstance == -1) {
-        return 1;
-    }
-    if (isinstance) {
-        singleton value;
-
-        if (_PyObject_LookupAttrId(obj, &PyId_value, &tmp) < 0) {
-            return 1;
-        }
-        if (tmp == NULL) {
-            PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from NameConstant");
-            return 1;
-        }
-        else {
-            int res;
-            res = obj2ast_singleton(tmp, &value, arena);
-            if (res != 0) goto failed;
-            Py_CLEAR(tmp);
-        }
-        *out = NameConstant(value, lineno, col_offset, arena);
-        if (*out == NULL) goto failed;
-        return 0;
-    }
-    isinstance = PyObject_IsInstance(obj, (PyObject*)Ellipsis_type);
-    if (isinstance == -1) {
-        return 1;
-    }
-    if (isinstance) {
-
-        *out = Ellipsis(lineno, col_offset, arena);
-        if (*out == NULL) goto failed;
-        return 0;
-    }
     isinstance = PyObject_IsInstance(obj, (PyObject*)Constant_type);
     if (isinstance == -1) {
         return 1;
@@ -8244,18 +7948,10 @@ PyInit__ast(void)
     if (PyDict_SetItemString(d, "Compare", (PyObject*)Compare_type) < 0) return
         NULL;
     if (PyDict_SetItemString(d, "Call", (PyObject*)Call_type) < 0) return NULL;
-    if (PyDict_SetItemString(d, "Num", (PyObject*)Num_type) < 0) return NULL;
-    if (PyDict_SetItemString(d, "Str", (PyObject*)Str_type) < 0) return NULL;
     if (PyDict_SetItemString(d, "FormattedValue",
         (PyObject*)FormattedValue_type) < 0) return NULL;
     if (PyDict_SetItemString(d, "JoinedStr", (PyObject*)JoinedStr_type) < 0)
         return NULL;
-    if (PyDict_SetItemString(d, "Bytes", (PyObject*)Bytes_type) < 0) return
-        NULL;
-    if (PyDict_SetItemString(d, "NameConstant", (PyObject*)NameConstant_type) <
-        0) return NULL;
-    if (PyDict_SetItemString(d, "Ellipsis", (PyObject*)Ellipsis_type) < 0)
-        return NULL;
     if (PyDict_SetItemString(d, "Constant", (PyObject*)Constant_type) < 0)
         return NULL;
     if (PyDict_SetItemString(d, "Attribute", (PyObject*)Attribute_type) < 0)
diff --git a/Python/ast.c b/Python/ast.c
index b93eb88dae7fce..1df6360aea771e 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -295,23 +295,6 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
             return 0;
         }
         return 1;
-    case Num_kind: {
-        PyObject *n = exp->v.Num.n;
-        if (!PyLong_CheckExact(n) && !PyFloat_CheckExact(n) &&
-            !PyComplex_CheckExact(n)) {
-            PyErr_SetString(PyExc_TypeError, "non-numeric type in Num");
-            return 0;
-        }
-        return 1;
-    }
-    case Str_kind: {
-        PyObject *s = exp->v.Str.s;
-        if (!PyUnicode_CheckExact(s)) {
-            PyErr_SetString(PyExc_TypeError, "non-string type in Str");
-            return 0;
-        }
-        return 1;
-    }
     case JoinedStr_kind:
         return validate_exprs(exp->v.JoinedStr.values, Load, 0);
     case FormattedValue_kind:
@@ -320,14 +303,6 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
         if (exp->v.FormattedValue.format_spec)
             return validate_expr(exp->v.FormattedValue.format_spec, Load);
         return 1;
-    case Bytes_kind: {
-        PyObject *b = exp->v.Bytes.s;
-        if (!PyBytes_CheckExact(b)) {
-            PyErr_SetString(PyExc_TypeError, "non-bytes type in Bytes");
-            return 0;
-        }
-        return 1;
-    }
     case Attribute_kind:
         return validate_expr(exp->v.Attribute.value, Load);
     case Subscript_kind:
@@ -339,10 +314,8 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
         return validate_exprs(exp->v.List.elts, ctx, 0);
     case Tuple_kind:
         return validate_exprs(exp->v.Tuple.elts, ctx, 0);
-    /* These last cases don't have any checking. */
+    /* This last case doesn't have any checking. */
     case Name_kind:
-    case NameConstant_kind:
-    case Ellipsis_kind:
         return 1;
     default:
         PyErr_SetString(PyExc_SystemError, "unexpected expression");
@@ -1040,19 +1013,23 @@ set_context(struct compiling *c, expr_ty e, expr_context_ty ctx, const node *n)
             break;
         case Dict_kind:
         case Set_kind:
-        case Num_kind:
-        case Str_kind:
-        case Bytes_kind:
         case JoinedStr_kind:
         case FormattedValue_kind:
             expr_name = "literal";
             break;
-        case NameConstant_kind:
-            expr_name = "keyword";
-            break;
-        case Ellipsis_kind:
-            expr_name = "Ellipsis";
+        case Constant_kind: {
+            PyObject *value = e->v.Constant.value;
+            if (value == Py_None || value == Py_False || value == Py_True) {
+                expr_name = "keyword";
+            }
+            else if (value == Py_Ellipsis) {
+                expr_name = "Ellipsis";
+            }
+            else {
+                expr_name = "literal";
+            }
             break;
+        }
         case Compare_kind:
             expr_name = "comparison";
             break;
@@ -2091,11 +2068,11 @@ ast_for_atom(struct compiling *c, const node *n)
         size_t len = strlen(s);
         if (len >= 4 && len <= 5) {
             if (!strcmp(s, "None"))
-                return NameConstant(Py_None, LINENO(n), n->n_col_offset, c->c_arena);
+                return Constant(Py_None, LINENO(n), n->n_col_offset, c->c_arena);
             if (!strcmp(s, "True"))
-                return NameConstant(Py_True, LINENO(n), n->n_col_offset, c->c_arena);
+                return Constant(Py_True, LINENO(n), n->n_col_offset, c->c_arena);
             if (!strcmp(s, "False"))
-                return NameConstant(Py_False, LINENO(n), n->n_col_offset, c->c_arena);
+                return Constant(Py_False, LINENO(n), n->n_col_offset, c->c_arena);
         }
         name = new_identifier(s, c);
         if (!name)
@@ -2144,10 +2121,10 @@ ast_for_atom(struct compiling *c, const node *n)
             Py_DECREF(pynum);
             return NULL;
         }
-        return Num(pynum, LINENO(n), n->n_col_offset, c->c_arena);
+        return Constant(pynum, LINENO(n), n->n_col_offset, c->c_arena);
     }
     case ELLIPSIS: /* Ellipsis */
-        return Ellipsis(LINENO(n), n->n_col_offset, c->c_arena);
+        return Constant(Py_Ellipsis, LINENO(n), n->n_col_offset, c->c_arena);
     case LPAR: /* some parenthesized expressions */
         ch = CHILD(n, 1);
 
@@ -4751,7 +4728,7 @@ typedef struct {
        expr_ty's, and then after that start dynamically allocating,
        doubling the number allocated each time. Note that the f-string
        f'{0}a{1}' contains 3 expr_ty's: 2 FormattedValue's, and one
-       Str for the literal 'a'. So you add expr_ty's about twice as
+       Constant for the literal 'a'. So you add expr_ty's about twice as
        fast as you add exressions in an f-string. */
 
     Py_ssize_t allocated;  /* Number we've allocated. */
@@ -4903,7 +4880,7 @@ FstringParser_Dealloc(FstringParser *state)
     ExprList_Dealloc(&state->expr_list);
 }
 
-/* Make a Str node, but decref the PyUnicode object being added. */
+/* Make a Constant node, but decref the PyUnicode object being added. */
 static expr_ty
 make_str_node_and_del(PyObject **str, struct compiling *c, const node* n)
 {
@@ -4914,7 +4891,7 @@ make_str_node_and_del(PyObject **str, struct compiling *c, const node* n)
         Py_DECREF(s);
         return NULL;
     }
-    return Str(s, LINENO(n), n->n_col_offset, c->c_arena);
+    return Constant(s, LINENO(n), n->n_col_offset, c->c_arena);
 }
 
 /* Add a non-f-string (that is, a regular literal string). str is
@@ -5002,11 +4979,11 @@ FstringParser_ConcatFstring(FstringParser *state, const char **str,
             break;
 
         /* We know we have an expression. Convert any existing string
-           to a Str node. */
+           to a Constant node. */
         if (!state->last_str) {
             /* Do nothing. No previous literal. */
         } else {
-            /* Convert the existing last_str literal to a Str node. */
+            /* Convert the existing last_str literal to a Constant node. */
             expr_ty str = make_str_node_and_del(&state->last_str, c, n);
             if (!str || ExprList_Append(&state->expr_list, str) < 0)
                 return -1;
@@ -5033,7 +5010,7 @@ FstringParser_ConcatFstring(FstringParser *state, const char **str,
 }
 
 /* Convert the partial state reflected in last_str and expr_list to an
-   expr_ty. The expr_ty can be a Str, or a JoinedStr. */
+   expr_ty. The expr_ty can be a Constant, or a JoinedStr. */
 static expr_ty
 FstringParser_Finish(FstringParser *state, struct compiling *c,
                      const node *n)
@@ -5055,7 +5032,7 @@ FstringParser_Finish(FstringParser *state, struct compiling *c,
         return make_str_node_and_del(&state->last_str, c, n);
     }
 
-    /* Create a Str node out of last_str, if needed. It will be the
+    /* Create a Constant node out of last_str, if needed. It will be the
        last node in our expression list. */
     if (state->last_str) {
         expr_ty str = make_str_node_and_del(&state->last_str, c, n);
@@ -5206,9 +5183,9 @@ parsestr(struct compiling *c, const node *n, int *bytesmode, int *rawmode,
 
 /* Accepts a STRING+ atom, and produces an expr_ty node. Run through
    each STRING atom, and process it as needed. For bytes, just
-   concatenate them together, and the result will be a Bytes node. For
+   concatenate them together, and the result will be a Constant node. For
    normal strings and f-strings, concatenate them together. The result
-   will be a Str node if there were no f-strings; a FormattedValue
+   will be a Constant node if there were no f-strings; a FormattedValue
    node if there's just an f-string (with no leading or trailing
    literals), or a JoinedStr node if there are multiple f-strings or
    any literals involved. */
@@ -5279,7 +5256,7 @@ parsestrplus(struct compiling *c, const node *n)
         /* Just return the bytes object and we're done. */
         if (PyArena_AddPyObject(c->c_arena, bytes_str) < 0)
             goto error;
-        return Bytes(bytes_str, LINENO(n), n->n_col_offset, c->c_arena);
+        return Constant(bytes_str, LINENO(n), n->n_col_offset, c->c_arena);
     }
 
     /* We're not a bytes string, bytes_str should never have been set. */
@@ -5304,9 +5281,6 @@ _PyAST_GetDocString(asdl_seq *body)
         return NULL;
     }
     expr_ty e = st->v.Expr.value;
-    if (e->kind == Str_kind) {
-        return e->v.Str.s;
-    }
     if (e->kind == Constant_kind && PyUnicode_CheckExact(e->v.Constant.value)) {
         return e->v.Constant.value;
     }
diff --git a/Python/ast_opt.c b/Python/ast_opt.c
index 5e57638e3d0172..1f9cb773ea7b95 100644
--- a/Python/ast_opt.c
+++ b/Python/ast_opt.c
@@ -5,47 +5,6 @@
 #include "ast.h"
 
 
-/* TODO: is_const and get_const_value are copied from Python/compile.c.
-   It should be deduped in the future.  Maybe, we can include this file
-   from compile.c?
-*/
-static int
-is_const(expr_ty e)
-{
-    switch (e->kind) {
-    case Constant_kind:
-    case Num_kind:
-    case Str_kind:
-    case Bytes_kind:
-    case Ellipsis_kind:
-    case NameConstant_kind:
-        return 1;
-    default:
-        return 0;
-    }
-}
-
-static PyObject *
-get_const_value(expr_ty e)
-{
-    switch (e->kind) {
-    case Constant_kind:
-        return e->v.Constant.value;
-    case Num_kind:
-        return e->v.Num.n;
-    case Str_kind:
-        return e->v.Str.s;
-    case Bytes_kind:
-        return e->v.Bytes.s;
-    case Ellipsis_kind:
-        return Py_Ellipsis;
-    case NameConstant_kind:
-        return e->v.NameConstant.value;
-    default:
-        Py_UNREACHABLE();
-    }
-}
-
 static int
 make_const(expr_ty node, PyObject *val, PyArena *arena)
 {
@@ -81,7 +40,7 @@ fold_unaryop(expr_ty node, PyArena *arena, int optimize)
 {
     expr_ty arg = node->v.UnaryOp.operand;
 
-    if (!is_const(arg)) {
+    if (arg->kind != Constant_kind) {
         /* Fold not into comparison */
         if (node->v.UnaryOp.op == Not && arg->kind == Compare_kind &&
                 asdl_seq_LEN(arg->v.Compare.ops) == 1) {
@@ -123,7 +82,7 @@ fold_unaryop(expr_ty node, PyArena *arena, int optimize)
         [UAdd] = PyNumber_Positive,
         [USub] = PyNumber_Negative,
     };
-    PyObject *newval = ops[node->v.UnaryOp.op](get_const_value(arg));
+    PyObject *newval = ops[node->v.UnaryOp.op](arg->v.Constant.value);
     return make_const(node, newval, arena);
 }
 
@@ -259,12 +218,12 @@ fold_binop(expr_ty node, PyArena *arena, int optimize)
     expr_ty lhs, rhs;
     lhs = node->v.BinOp.left;
     rhs = node->v.BinOp.right;
-    if (!is_const(lhs) || !is_const(rhs)) {
+    if (lhs->kind != Constant_kind || rhs->kind != Constant_kind) {
         return 1;
     }
 
-    PyObject *lv = get_const_value(lhs);
-    PyObject *rv = get_const_value(rhs);
+    PyObject *lv = lhs->v.Constant.value;
+    PyObject *rv = rhs->v.Constant.value;
     PyObject *newval;
 
     switch (node->v.BinOp.op) {
@@ -316,7 +275,7 @@ make_const_tuple(asdl_seq *elts)
 {
     for (int i = 0; i < asdl_seq_LEN(elts); i++) {
         expr_ty e = (expr_ty)asdl_seq_GET(elts, i);
-        if (!is_const(e)) {
+        if (e->kind != Constant_kind) {
             return NULL;
         }
     }
@@ -328,7 +287,7 @@ make_const_tuple(asdl_seq *elts)
 
     for (int i = 0; i < asdl_seq_LEN(elts); i++) {
         expr_ty e = (expr_ty)asdl_seq_GET(elts, i);
-        PyObject *v = get_const_value(e);
+        PyObject *v = e->v.Constant.value;
         Py_INCREF(v);
         PyTuple_SET_ITEM(newval, i, v);
     }
@@ -357,16 +316,16 @@ fold_subscr(expr_ty node, PyArena *arena, int optimize)
     arg = node->v.Subscript.value;
     slice = node->v.Subscript.slice;
     if (node->v.Subscript.ctx != Load ||
-            !is_const(arg) ||
+            arg->kind != Constant_kind ||
             /* TODO: handle other types of slices */
             slice->kind != Index_kind ||
-            !is_const(slice->v.Index.value))
+            slice->v.Index.value->kind != Constant_kind)
     {
         return 1;
     }
 
     idx = slice->v.Index.value;
-    newval = PyObject_GetItem(get_const_value(arg), get_const_value(idx));
+    newval = PyObject_GetItem(arg->v.Constant.value, idx->v.Constant.value);
     return make_const(node, newval, arena);
 }
 
diff --git a/Python/ast_unparse.c b/Python/ast_unparse.c
index 725ce31fe3c037..6303ebbcac9298 100644
--- a/Python/ast_unparse.c
+++ b/Python/ast_unparse.c
@@ -567,8 +567,6 @@ append_fstring_element(_PyUnicodeWriter *writer, expr_ty e, bool is_format_spec)
     switch (e->kind) {
     case Constant_kind:
         return append_fstring_unicode(writer, e->v.Constant.value);
-    case Str_kind:
-        return append_fstring_unicode(writer, e->v.Str.s);
     case JoinedStr_kind:
         return append_joinedstr(writer, e, is_format_spec);
     case FormattedValue_kind:
@@ -694,8 +692,7 @@ append_ast_attribute(_PyUnicodeWriter *writer, expr_ty e)
 
     /* Special case: integers require a space for attribute access to be
        unambiguous.  Floats and complex numbers don't but work with it, too. */
-    if (e->v.Attribute.value->kind == Num_kind ||
-        e->v.Attribute.value->kind == Constant_kind)
+    if (e->v.Attribute.value->kind == Constant_kind)
     {
         period = " .";
     }
@@ -841,21 +838,14 @@ append_ast_expr(_PyUnicodeWriter *writer, expr_ty e, int level)
     case Call_kind:
         return append_ast_call(writer, e);
     case Constant_kind:
+        if (e->v.Constant.value == Py_Ellipsis) {
+            APPEND_STR_FINISH("...");
+        }
         return append_repr(writer, e->v.Constant.value);
-    case Num_kind:
-        return append_repr(writer, e->v.Num.n);
-    case Str_kind:
-        return append_repr(writer, e->v.Str.s);
     case JoinedStr_kind:
         return append_joinedstr(writer, e, false);
     case FormattedValue_kind:
         return append_formattedvalue(writer, e, false);
-    case Bytes_kind:
-        return append_repr(writer, e->v.Bytes.s);
-    case Ellipsis_kind:
-        APPEND_STR_FINISH("...");
-    case NameConstant_kind:
-        return append_repr(writer, e->v.NameConstant.value);
     /* The following exprs can be assignment targets. */
     case Attribute_kind:
         return append_ast_attribute(writer, e);
diff --git a/Python/compile.c b/Python/compile.c
index 707da79ab66278..ab52f71dd2f6a2 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -1398,43 +1398,6 @@ compiler_addop_j(struct compiler *c, int opcode, basicblock *b, int absolute)
     } \
 }
 
-static int
-is_const(expr_ty e)
-{
-    switch (e->kind) {
-    case Constant_kind:
-    case Num_kind:
-    case Str_kind:
-    case Bytes_kind:
-    case Ellipsis_kind:
-    case NameConstant_kind:
-        return 1;
-    default:
-        return 0;
-    }
-}
-
-static PyObject *
-get_const_value(expr_ty e)
-{
-    switch (e->kind) {
-    case Constant_kind:
-        return e->v.Constant.value;
-    case Num_kind:
-        return e->v.Num.n;
-    case Str_kind:
-        return e->v.Str.s;
-    case Bytes_kind:
-        return e->v.Bytes.s;
-    case Ellipsis_kind:
-        return Py_Ellipsis;
-    case NameConstant_kind:
-        return e->v.NameConstant.value;
-    default:
-        Py_UNREACHABLE();
-    }
-}
-
 /* Search if variable annotations are present statically in a block. */
 
 static int
@@ -2568,7 +2531,7 @@ static int
 compiler_return(struct compiler *c, stmt_ty s)
 {
     int preserve_tos = ((s->v.Return.value != NULL) &&
-                        !is_const(s->v.Return.value));
+                        (s->v.Return.value->kind != Constant_kind));
     if (c->u->u_ste->ste_type != FunctionBlock)
         return compiler_error(c, "'return' outside function");
     if (s->v.Return.value != NULL &&
@@ -3054,7 +3017,7 @@ compiler_visit_stmt_expr(struct compiler *c, expr_ty value)
         return 1;
     }
 
-    if (is_const(value)) {
+    if (value->kind == Constant_kind) {
         /* ignore constant statement */
         return 1;
     }
@@ -3502,7 +3465,7 @@ are_all_items_const(asdl_seq *seq, Py_ssize_t begin, Py_ssize_t end)
     Py_ssize_t i;
     for (i = begin; i < end; i++) {
         expr_ty key = (expr_ty)asdl_seq_GET(seq, i);
-        if (key == NULL || !is_const(key))
+        if (key == NULL || key->kind != Constant_kind)
             return 0;
     }
     return 1;
@@ -3522,7 +3485,7 @@ compiler_subdict(struct compiler *c, expr_ty e, Py_ssize_t begin, Py_ssize_t end
             return 0;
         }
         for (i = begin; i < end; i++) {
-            key = get_const_value((expr_ty)asdl_seq_GET(e->v.Dict.keys, i));
+            key = ((expr_ty)asdl_seq_GET(e->v.Dict.keys, i))->v.Constant.value;
             Py_INCREF(key);
             PyTuple_SET_ITEM(keys, i - begin, key);
         }
@@ -4244,8 +4207,8 @@ compiler_visit_keyword(struct compiler *c, keyword_ty k)
 static int
 expr_constant(expr_ty e)
 {
-    if (is_const(e)) {
-        return PyObject_IsTrue(get_const_value(e));
+    if (e->kind == Constant_kind) {
+        return PyObject_IsTrue(e->v.Constant.value);
     }
     return -1;
 }
@@ -4505,25 +4468,10 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
     case Constant_kind:
         ADDOP_LOAD_CONST(c, e->v.Constant.value);
         break;
-    case Num_kind:
-        ADDOP_LOAD_CONST(c, e->v.Num.n);
-        break;
-    case Str_kind:
-        ADDOP_LOAD_CONST(c, e->v.Str.s);
-        break;
     case JoinedStr_kind:
         return compiler_joined_str(c, e);
     case FormattedValue_kind:
         return compiler_formatted_value(c, e);
-    case Bytes_kind:
-        ADDOP_LOAD_CONST(c, e->v.Bytes.s);
-        break;
-    case Ellipsis_kind:
-        ADDOP_LOAD_CONST(c, Py_Ellipsis);
-        break;
-    case NameConstant_kind:
-        ADDOP_LOAD_CONST(c, e->v.NameConstant.value);
-        break;
     /* The following exprs can be assignment targets. */
     case Attribute_kind:
         if (e->v.Attribute.ctx != AugStore)
diff --git a/Python/symtable.c b/Python/symtable.c
index 3e8c6f5dae30c9..63541bfafd0403 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -1461,11 +1461,6 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
         VISIT_SEQ(st, expr, e->v.JoinedStr.values);
         break;
     case Constant_kind:
-    case Num_kind:
-    case Str_kind:
-    case Bytes_kind:
-    case Ellipsis_kind:
-    case NameConstant_kind:
         /* Nothing to do here. */
         break;
     /* The following exprs can be assignment targets. */
diff --git a/Tools/clinic/clinic.py b/Tools/clinic/clinic.py
index a6a43d1361d0e1..3203c0d6c5b67f 100755
--- a/Tools/clinic/clinic.py
+++ b/Tools/clinic/clinic.py
@@ -3840,9 +3840,6 @@ def bad_node(self, node):
                         # "starred": "a = [1, 2, 3]; *a"
                         visit_Starred = bad_node
 
-                        # allow ellipsis, for now
-                        # visit_Ellipsis = bad_node
-
                     blacklist = DetectBadNodes()
                     blacklist.visit(module)
                     bad = blacklist.bad
@@ -3868,10 +3865,14 @@ def bad_node(self, node):
                     py_default = 'None'
                     c_default = "NULL"
                 elif (isinstance(expr, ast.BinOp) or
-                    (isinstance(expr, ast.UnaryOp) and not isinstance(expr.operand, ast.Num))):
+                    (isinstance(expr, ast.UnaryOp) and
+                     not (isinstance(expr.operand, ast.Num) or
+                          isinstance(expr.operand, ast.Constant) and
+                          type(expr.operand.value) in (int, float, complex))
+                    )):
                     c_default = kwargs.get("c_default")
                     if not (isinstance(c_default, str) and c_default):
-                        fail("When you specify an expression (" + repr(default) + ") as your default value,\nyou MUST specify a valid c_default.")
+                        fail("When you specify an expression (" + repr(default) + ") as your default value,\nyou MUST specify a valid c_default." + ast.dump(expr))
                     py_default = default
                     value = unknown
                 elif isinstance(expr, ast.Attribute):
@@ -3946,6 +3947,9 @@ def bad_node(self, node):
         self.function.parameters[parameter_name] = p
 
     def parse_converter(self, annotation):
+        if isinstance(annotation, ast.Constant) and type(annotation.value) is str:
+            return annotation.value, True, {}
+
         if isinstance(annotation, ast.Str):
             return annotation.s, True, {}
 
diff --git a/Tools/parser/unparse.py b/Tools/parser/unparse.py
index 7e1cc4ea5db950..82c3c776807283 100644
--- a/Tools/parser/unparse.py
+++ b/Tools/parser/unparse.py
@@ -329,12 +329,6 @@ def _AsyncWith(self, t):
         self.leave()
 
     # expr
-    def _Bytes(self, t):
-        self.write(repr(t.s))
-
-    def _Str(self, tree):
-        self.write(repr(tree.s))
-
     def _JoinedStr(self, t):
         self.write("f")
         string = io.StringIO()
@@ -352,10 +346,6 @@ def _fstring_JoinedStr(self, t, write):
             meth = getattr(self, "_fstring_" + type(value).__name__)
             meth(value, write)
 
-    def _fstring_Str(self, t, write):
-        value = t.s.replace("{", "{{").replace("}", "}}")
-        write(value)
-
     def _fstring_Constant(self, t, write):
         assert isinstance(t.value, str)
         value = t.value.replace("{", "{{").replace("}", "}}")
@@ -384,6 +374,7 @@ def _Name(self, t):
 
     def _write_constant(self, value):
         if isinstance(value, (float, complex)):
+            # Substitute overflowing decimal literal for AST infinities.
             self.write(repr(value).replace("inf", INFSTR))
         else:
             self.write(repr(value))
@@ -398,16 +389,11 @@ def _Constant(self, t):
             else:
                 interleave(lambda: self.write(", "), self._write_constant, value)
             self.write(")")
+        elif value is ...:
+            self.write("...")
         else:
             self._write_constant(t.value)
 
-    def _NameConstant(self, t):
-        self.write(repr(t.value))
-
-    def _Num(self, t):
-        # Substitute overflowing decimal literal for AST infinities.
-        self.write(repr(t.n).replace("inf", INFSTR))
-
     def _List(self, t):
         self.write("[")
         interleave(lambda: self.write(", "), self.dispatch, t.elts)
@@ -539,8 +525,7 @@ def _Attribute(self,t):
         # Special case: 3.__abs__() is a syntax error, so if t.value
         # is an integer literal then we need to either parenthesize
         # it or add an extra space to get 3 .__abs__().
-        if ((isinstance(t.value, ast.Num) and isinstance(t.value.n, int))
-           or (isinstance(t.value, ast.Constant) and isinstance(t.value.value, int))):
+        if isinstance(t.value, ast.Constant) and isinstance(t.value.value, int):
             self.write(" ")
         self.write(".")
         self.write(t.attr)

From a0aefdcc5327a9264296feb18c3213f7aeced6c1 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Thu, 20 Sep 2018 18:13:15 +0300
Subject: [PATCH 2/6] Fix Argument Clinic on Python 3.5.

---
 Tools/clinic/clinic.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Tools/clinic/clinic.py b/Tools/clinic/clinic.py
index 3203c0d6c5b67f..ca8096f43a6ffd 100755
--- a/Tools/clinic/clinic.py
+++ b/Tools/clinic/clinic.py
@@ -3867,8 +3867,9 @@ def bad_node(self, node):
                 elif (isinstance(expr, ast.BinOp) or
                     (isinstance(expr, ast.UnaryOp) and
                      not (isinstance(expr.operand, ast.Num) or
-                          isinstance(expr.operand, ast.Constant) and
-                          type(expr.operand.value) in (int, float, complex))
+                          (hasattr(ast, 'Constant') and
+                           isinstance(expr.operand, ast.Constant) and
+                           type(expr.operand.value) in (int, float, complex)))
                     )):
                     c_default = kwargs.get("c_default")
                     if not (isinstance(c_default, str) and c_default):
@@ -3947,7 +3948,9 @@ def bad_node(self, node):
         self.function.parameters[parameter_name] = p
 
     def parse_converter(self, annotation):
-        if isinstance(annotation, ast.Constant) and type(annotation.value) is str:
+        if (hasattr(ast, 'Constant') and
+            isinstance(annotation, ast.Constant) and
+            type(annotation.value) is str):
             return annotation.value, True, {}
 
         if isinstance(annotation, ast.Str):

From e18498694af6855429b011ddbd60a8637fff603e Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Fri, 21 Sep 2018 23:34:10 +0300
Subject: [PATCH 3/6] Fix isinstance and add support of subclasses.

---
 Lib/ast.py           | 93 +++++++++++++++++++-------------------------
 Lib/test/test_ast.py | 89 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+), 52 deletions(-)

diff --git a/Lib/ast.py b/Lib/ast.py
index fab19fbdf3c578..de3df1473e5ea2 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -323,6 +323,9 @@ def generic_visit(self, node):
         return node
 
 
+# The following code is for backward compatibility.
+# It will be removed in future.
+
 def _getter(self):
     return self.value
 
@@ -332,66 +335,52 @@ def _setter(self, value):
 Constant.n = property(_getter, _setter)
 Constant.s = property(_getter, _setter)
 
-_unspecified = object()
-
+class _ABC(type):
 
-class Num(Constant):
-    _fields = ('n',)
-
-    def __new__(cls, s=_unspecified, **kwargs):
-        if s is _unspecified:
-            return Constant(**kwargs)
-        return Constant(value=s, **kwargs)
+    def __instancecheck__(cls, inst):
+        if not isinstance(inst, Constant):
+            return False
+        if cls in _const_types:
+            try:
+                value = inst.value
+            except AttributeError:
+                return False
+            else:
+                return type(value) in _const_types[cls]
+        return type.__instancecheck__(cls, inst)
 
-    @staticmethod
-    def __instancecheck__(instance):
-        return (isinstance(instance, Constant) and
-                type(instance.value) in (int, float, complex))
+def _new(cls, *args, **kwargs):
+    if cls in _const_types:
+        return Constant(*args, **kwargs)
+    return Constant.__new__(cls, *args, **kwargs)
 
+class Num(Constant, metaclass=_ABC):
+    _fields = ('n',)
+    __new__ = _new
 
-class Str(Constant):
+class Str(Constant, metaclass=_ABC):
     _fields = ('s',)
+    __new__ = _new
 
-    def __new__(cls, s=_unspecified, **kwargs):
-        if s is _unspecified:
-            return Constant(**kwargs)
-        return Constant(value=s, **kwargs)
-
-    @staticmethod
-    def __instancecheck__(instance):
-        return isinstance(instance, Constant) and type(instance.value) is str
-
-
-class Bytes(Constant):
+class Bytes(Constant, metaclass=_ABC):
     _fields = ('s',)
+    __new__ = _new
 
-    def __new__(cls, s=_unspecified, **kwargs):
-        if s is _unspecified:
-            return Constant(**kwargs)
-        return Constant(value=s, **kwargs)
+class NameConstant(Constant, metaclass=_ABC):
+    __new__ = _new
 
-    @staticmethod
-    def __instancecheck__(instance):
-        return isinstance(instance, Constant) and type(instance.value) is bytes
-
-
-class NameConstant(Constant):
-    def __new__(cls, *args, **kwargs):
-        return Constant(*args, **kwargs)
-
-    @staticmethod
-    def __instancecheck__(instance):
-        return (isinstance(instance, Constant) and
-                (instance.value is False or instance.value is True or
-                 instance.value is None))
-
-
-class Ellipsis(Constant):
+class Ellipsis(Constant, metaclass=_ABC):
     _fields = ()
 
-    def __new__(cls, **kwargs):
-        return Constant(..., **kwargs)
-
-    @staticmethod
-    def __instancecheck__(instance):
-        return isinstance(instance, Constant) and instance.value is ...
+    def __new__(cls, *args, **kwargs):
+        if cls is Ellipsis:
+            return Constant(..., *args, **kwargs)
+        return Constant.__new__(cls, *args, **kwargs)
+
+_const_types = {
+    Num: (int, float, complex),
+    Str: (str,),
+    Bytes: (bytes,),
+    NameConstant: (type(None), bool),
+    Ellipsis: (type(...),),
+}
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 7bfb31a56263cb..7cda5ea7bc9d02 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -330,6 +330,95 @@ def test_classattrs(self):
         self.assertRaises(TypeError, ast.Num, 1, 2)
         self.assertRaises(TypeError, ast.Num, 1, 2, lineno=0)
 
+        self.assertEqual(ast.Num(42).n, 42)
+        self.assertEqual(ast.Num(4.25).n, 4.25)
+        self.assertEqual(ast.Num(4.25j).n, 4.25j)
+        self.assertEqual(ast.Str('42').s, '42')
+        self.assertEqual(ast.Bytes(b'42').s, b'42')
+        self.assertIs(ast.NameConstant(True).value, True)
+        self.assertIs(ast.NameConstant(False).value, False)
+        self.assertIs(ast.NameConstant(None).value, None)
+
+        self.assertEqual(ast.Constant(42).value, 42)
+        self.assertEqual(ast.Constant(4.25).value, 4.25)
+        self.assertEqual(ast.Constant(4.25j).value, 4.25j)
+        self.assertEqual(ast.Constant('42').value, '42')
+        self.assertEqual(ast.Constant(b'42').value, b'42')
+        self.assertIs(ast.Constant(True).value, True)
+        self.assertIs(ast.Constant(False).value, False)
+        self.assertIs(ast.Constant(None).value, None)
+        self.assertIs(ast.Constant(...).value, ...)
+
+    def test_realtype(self):
+        self.assertEqual(type(ast.Num(42)), ast.Constant)
+        self.assertEqual(type(ast.Num(4.25)), ast.Constant)
+        self.assertEqual(type(ast.Num(4.25j)), ast.Constant)
+        self.assertEqual(type(ast.Str('42')), ast.Constant)
+        self.assertEqual(type(ast.Bytes(b'42')), ast.Constant)
+        self.assertEqual(type(ast.NameConstant(True)), ast.Constant)
+        self.assertEqual(type(ast.NameConstant(False)), ast.Constant)
+        self.assertEqual(type(ast.NameConstant(None)), ast.Constant)
+        self.assertEqual(type(ast.Ellipsis()), ast.Constant)
+
+    def test_isinstance(self):
+        self.assertTrue(isinstance(ast.Num(42), ast.Num))
+        self.assertTrue(isinstance(ast.Num(4.2), ast.Num))
+        self.assertTrue(isinstance(ast.Num(4.2j), ast.Num))
+        self.assertTrue(isinstance(ast.Str('42'), ast.Str))
+        self.assertTrue(isinstance(ast.Bytes(b'42'), ast.Bytes))
+        self.assertTrue(isinstance(ast.NameConstant(True), ast.NameConstant))
+        self.assertTrue(isinstance(ast.NameConstant(False), ast.NameConstant))
+        self.assertTrue(isinstance(ast.NameConstant(None), ast.NameConstant))
+        self.assertTrue(isinstance(ast.Ellipsis(), ast.Ellipsis))
+
+        self.assertTrue(isinstance(ast.Constant(42), ast.Num))
+        self.assertTrue(isinstance(ast.Constant(4.2), ast.Num))
+        self.assertTrue(isinstance(ast.Constant(4.2j), ast.Num))
+        self.assertTrue(isinstance(ast.Constant('42'), ast.Str))
+        self.assertTrue(isinstance(ast.Constant(b'42'), ast.Bytes))
+        self.assertTrue(isinstance(ast.Constant(True), ast.NameConstant))
+        self.assertTrue(isinstance(ast.Constant(False), ast.NameConstant))
+        self.assertTrue(isinstance(ast.Constant(None), ast.NameConstant))
+        self.assertTrue(isinstance(ast.Constant(...), ast.Ellipsis))
+
+        self.assertFalse(isinstance(ast.Str('42'), ast.Num))
+        self.assertFalse(isinstance(ast.Num(42), ast.Str))
+        self.assertFalse(isinstance(ast.Str('42'), ast.Bytes))
+        self.assertFalse(isinstance(ast.Num(42), ast.NameConstant))
+        self.assertFalse(isinstance(ast.Num(42), ast.Ellipsis))
+
+        self.assertFalse(isinstance(ast.Constant('42'), ast.Num))
+        self.assertFalse(isinstance(ast.Constant(42), ast.Str))
+        self.assertFalse(isinstance(ast.Constant('42'), ast.Bytes))
+        self.assertFalse(isinstance(ast.Constant(42), ast.NameConstant))
+        self.assertFalse(isinstance(ast.Constant(42), ast.Ellipsis))
+
+        self.assertFalse(isinstance(ast.Constant(), ast.Num))
+        self.assertFalse(isinstance(ast.Constant(), ast.Str))
+        self.assertFalse(isinstance(ast.Constant(), ast.Bytes))
+        self.assertFalse(isinstance(ast.Constant(), ast.NameConstant))
+        self.assertFalse(isinstance(ast.Constant(), ast.Ellipsis))
+
+    def test_subclasses(self):
+        class N(ast.Num):
+            def __init__(self, *args, **kwargs):
+                super().__init__(*args, **kwargs)
+                self.z = 'spam'
+        class N2(ast.Num):
+            pass
+
+        n = N(42)
+        self.assertEqual(n.n, 42)
+        self.assertEqual(n.z, 'spam')
+        self.assertEqual(type(n), N)
+        self.assertTrue(isinstance(n, N))
+        self.assertTrue(isinstance(n, ast.Num))
+        self.assertFalse(isinstance(n, N2))
+        self.assertFalse(isinstance(ast.Num(42), N))
+        n = N(n=42)
+        self.assertEqual(n.n, 42)
+        self.assertEqual(type(n), N)
+
     def test_module(self):
         body = [ast.Num(42)]
         x = ast.Module(body)

From 8e6472020aa2e90d5e458f656c0a6a46def54803 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sat, 22 Sep 2018 00:28:32 +0300
Subject: [PATCH 4/6] Add the deprecated directive in the module documentation.

---
 Doc/library/ast.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index a727dd6a6fbca9..97ce2f5281b5a5 100644
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -90,6 +90,13 @@ Node classes
       node = ast.UnaryOp(ast.USub(), ast.Constant(5, lineno=0, col_offset=0),
                          lineno=0, col_offset=0)
 
+.. deprecated:: 3.8
+
+   Class :class:`ast.Constant` is now used for all constants. Old classes
+   :class:`ast.Num`, :class:`ast.Str`, :class:`ast.Bytes`,
+   :class:`ast.NameConstant` and :class:`ast.Ellipsis` are still available,
+   but they will be removed in future Python releases.
+
 
 .. _abstract-grammar:
 

From 14d788eb897283fa9348edfcab989c02116c25fe Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sat, 22 Sep 2018 12:33:37 +0300
Subject: [PATCH 5/6] Fix tests.

---
 Lib/test/test_ast.py    | 3 +--
 Lib/test/test_future.py | 2 +-
 Lib/test/test_pyclbr.py | 3 ++-
 Python/ast_unparse.c    | 8 ++++----
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 7cda5ea7bc9d02..10be02eee0c03c 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -726,8 +726,7 @@ def mod(self, mod, msg=None, mode="exec", *, exc=ValueError):
         else:
             with self.assertRaises(exc) as cm:
                 compile(mod, "<test>", mode)
-            if msg is not None:
-                self.assertIn(msg, str(cm.exception))
+            self.assertIn(msg, str(cm.exception))
 
     def expr(self, node, msg=None, *, exc=ValueError):
         mod = ast.Module([ast.Expr(node)])
diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
index 61cd63479d85e9..e8f2f761559030 100644
--- a/Lib/test/test_future.py
+++ b/Lib/test/test_future.py
@@ -230,7 +230,7 @@ def test_annotations(self):
         eq("lukasz.langa.pl")
         eq("call.me(maybe)")
         eq("1 .real")
-        eq("1.0 .real")
+        eq("1.0.real")
         eq("....__class__")
         eq("list[str]")
         eq("dict[str, int]")
diff --git a/Lib/test/test_pyclbr.py b/Lib/test/test_pyclbr.py
index eaab591f74efe4..9e970d9df041b8 100644
--- a/Lib/test/test_pyclbr.py
+++ b/Lib/test/test_pyclbr.py
@@ -144,7 +144,8 @@ def defined_in(item, module):
 
     def test_easy(self):
         self.checkModule('pyclbr')
-        self.checkModule('ast')
+        # XXX: Metaclasses are not supported
+        # self.checkModule('ast')
         self.checkModule('doctest', ignore=("TestResults", "_SpoofOut",
                                             "DocTestCase", '_DocTestSuite'))
         self.checkModule('difflib', ignore=("Match",))
diff --git a/Python/ast_unparse.c b/Python/ast_unparse.c
index 6303ebbcac9298..56ea3c424c5bbe 100644
--- a/Python/ast_unparse.c
+++ b/Python/ast_unparse.c
@@ -688,12 +688,12 @@ static int
 append_ast_attribute(_PyUnicodeWriter *writer, expr_ty e)
 {
     const char *period;
-    APPEND_EXPR(e->v.Attribute.value, PR_ATOM);
+    expr_ty v = e->v.Attribute.value;
+    APPEND_EXPR(v, PR_ATOM);
 
     /* Special case: integers require a space for attribute access to be
-       unambiguous.  Floats and complex numbers don't but work with it, too. */
-    if (e->v.Attribute.value->kind == Constant_kind)
-    {
+       unambiguous. */
+    if (v->kind == Constant_kind && PyLong_CheckExact(v->v.Constant.value)) {
         period = " .";
     }
     else {

From 0031ce8e35e88f4f4df24259435c416e120fcac9 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sun, 23 Sep 2018 08:37:25 +0300
Subject: [PATCH 6/6] Fix mark up in NEWS.

---
 .../next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst b/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst
index 74fafb44b6da84..9be4bf89008d9c 100644
--- a/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst
+++ b/Misc/NEWS.d/next/Library/2018-09-20-17-35-05.bpo-32892.TOUBdg.rst
@@ -1,4 +1,4 @@
 The parser now represents all constants as :class:`ast.Constant` instead of
-using specific constant AST types (``Num``, ``Str``,``Bytes``,
+using specific constant AST types (``Num``, ``Str``, ``Bytes``,
 ``NameConstant`` and ``Ellipsis``). These classes are considered deprecated
 and will be removed in future Python versions.