From 50ca4f18ca58254da06f84005d575044c4e2896a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexander=20B=C3=B6hn?= <fish2000@users.noreply.github.com>
Date: Thu, 11 Oct 2018 23:07:01 -0400
Subject: [PATCH 1/2] bpo-34963: Updated NewType according to latest PR notes
 ... also added appropriate tests

---
 Lib/test/test_typing.py                       | 19 ++++++++++
 Lib/typing.py                                 | 35 +++++++++++++------
 .../2018-10-11-23-14-13.bpo-34963.fNy13b.rst  |  3 ++
 3 files changed, 46 insertions(+), 11 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2018-10-11-23-14-13.bpo-34963.fNy13b.rst

diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 6d8cc5319fb121..11ef0a49c71e41 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -2414,6 +2414,25 @@ def test_basic(self):
         self.assertIsInstance(UserName('Joe'), str)
         self.assertEqual(UserId(5) + 1, 6)
 
+    def test_definitions(self):
+        UserId = NewType('UserId', int)
+        UserName = NewType('UserName', str)
+        self.assertEqual(UserId.__name__, 'UserId')
+        self.assertEqual(UserId.__qualname__, 'UserId')
+        self.assertIs(UserId.__supertype__, int)
+        self.assertIsInstance(UserId, NewType)
+        self.assertEqual(UserName.__name__, 'UserName')
+        self.assertEqual(UserName.__qualname__, 'UserName')
+        self.assertIs(UserName.__supertype__, str)
+        self.assertIsInstance(UserName, NewType)
+        self.assertNotEqual(hash(UserId), hash(UserName))
+
+    def test_repr(self):
+        UserId = NewType('UserId', int)
+        UserName = NewType('UserName', str)
+        self.assertEqual(repr(UserId), "NewType<UserId:int>")
+        self.assertEqual(repr(UserName), "NewType<UserName:str>")
+
     def test_errors(self):
         UserId = NewType('UserId', int)
         UserName = NewType('UserName', str)
diff --git a/Lib/typing.py b/Lib/typing.py
index cfcbb3b7632842..19f550625da3d7 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1409,12 +1409,13 @@ def __new__(self, typename, fields=None, **kwargs):
                             " can be provided to NamedTuple, not both")
         return _make_nmtuple(typename, fields)
 
+class NewType:
 
-def NewType(name, tp):
-    """NewType creates simple unique types with almost zero
-    runtime overhead. NewType(name, tp) is considered a subtype of tp
-    by static type checkers. At runtime, NewType(name, tp) returns
-    a dummy function that simply returns its argument. Usage::
+    """NewType creates simple unique types with almost zero runtime
+    overhead. `NewType(name, tp)` is considered a subtype of `tp`
+    by static type checkers. At runtime, NewType(name, tp) creates
+    a callable instance that simply returns its argument when called.
+    Usage::
 
         UserId = NewType('UserId', int)
 
@@ -1429,18 +1430,30 @@ def name_by_id(user_id: UserId) -> str:
         num = UserId(5) + 1     # type: int
     """
 
-    def new_type(x):
-        return x
+    __slots__ = ('__name__', '__qualname__', '__supertype__')
+
+    def __init__(self, name, tp):
+        self.__name__ = self.__qualname__ = name
+        self.__supertype__ = tp
+
+    @staticmethod
+    def __call__(arg):
+        return arg
 
-    new_type.__name__ = name
-    new_type.__supertype__ = tp
-    return new_type
+    def __repr__(self):
+        """ NewType reprs are in the form:
+           “NewTyprClassName<typename:supertypename>”
+        """
+        return f"{type(self).__name__}<" \
+               f"{self.__qualname__}:" \
+               f"{self.__supertype__.__name__}>"
 
+    def __hash__(self):
+        return hash((self.__name__, self.__supertype__))
 
 # Python-version-specific alias (Python 2: unicode; Python 3: str)
 Text = str
 
-
 # Constant that's True when type checking, but False here.
 TYPE_CHECKING = False
 
diff --git a/Misc/NEWS.d/next/Library/2018-10-11-23-14-13.bpo-34963.fNy13b.rst b/Misc/NEWS.d/next/Library/2018-10-11-23-14-13.bpo-34963.fNy13b.rst
new file mode 100644
index 00000000000000..eed1b450fbdbc9
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-10-11-23-14-13.bpo-34963.fNy13b.rst
@@ -0,0 +1,3 @@
+Updated the `typing.NewType(…)` function to create real callable types –
+This allows the generated types to furnish a real __repr__ function, while
+retaining the same behavior (specifically, the near-zero runtime overhead).

From 6a753398d74cb79099a4d8e88dc8eb7343e8c806 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexander=20B=C3=B6hn?= <fish2000@users.noreply.github.com>
Date: Tue, 16 Oct 2018 13:24:12 -0400
Subject: [PATCH 2/2] =?UTF-8?q?Corrected=20typos=20in=20NewType.=5F=5Frepr?=
 =?UTF-8?q?=5F=5F(=E2=80=A6)=20docstring?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Lib/typing.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/typing.py b/Lib/typing.py
index 19f550625da3d7..7973a7c4aafc9d 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1442,7 +1442,8 @@ def __call__(arg):
 
     def __repr__(self):
         """ NewType reprs are in the form:
-           “NewTyprClassName<typename:supertypename>”
+           “NewTClassName<typename:supertypename>”, e.g.:
+           `NewType<UserId:int>`
         """
         return f"{type(self).__name__}<" \
                f"{self.__qualname__}:" \