From a7e5e1d5a3f9e4ade420608d7ca79661eb7a2e08 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Mon, 23 Jul 2018 10:51:42 +0100
Subject: [PATCH 1/2] support pep-563 -- Postponed Evaluation of Annotations

---
 05-annotations.py           | 3 ++-
 07-metaclasses.py           | 3 ++-
 08-interlude_dataclasses.py | 8 +++++---
 09-meta_dataclasses.py      | 3 ++-
 11-ast.py                   | 3 ++-
 5 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/05-annotations.py b/05-annotations.py
index 8fc3a69..5071c6f 100644
--- a/05-annotations.py
+++ b/05-annotations.py
@@ -1,4 +1,5 @@
 from math import pi
+import typing
 
 
 class TypeChecker:
@@ -17,7 +18,7 @@ def __set__(self, instance, value):
 
 
 def type_check(cls):
-    for var_name, var_type in cls.__annotations__.items():
+    for var_name, var_type in typing.get_type_hints(cls).items():
         class Checker(TypeChecker):
             required_type = var_type
 
diff --git a/07-metaclasses.py b/07-metaclasses.py
index 15a9cb4..721ff1f 100644
--- a/07-metaclasses.py
+++ b/07-metaclasses.py
@@ -1,4 +1,5 @@
 from math import pi
+import typing
 
 
 class TypeChecker:
@@ -17,7 +18,7 @@ def __set__(self, instance, value):
 
 
 def type_check(cls):
-    for var_name, var_type in cls.__annotations__.items():
+    for var_name, var_type in typing.get_type_hints(cls).items():
         class Checker(TypeChecker):
             required_type = var_type
 
diff --git a/08-interlude_dataclasses.py b/08-interlude_dataclasses.py
index 61d7fde..6a2a8ee 100644
--- a/08-interlude_dataclasses.py
+++ b/08-interlude_dataclasses.py
@@ -1,9 +1,11 @@
+import typing
+
 def dataclass(cls):
     def __init__(self, *args, **kwargs):
-        for k, v in zip(cls.__annotations__.keys(), args):
+        for k, v in zip(typing.get_type_hints(cls).keys(), args):
             setattr(self, k, v)
         for k, v in kwargs.items():
-            if k not in cls.__annotations__:
+            if k not in typing.get_type_hints(cls):
                 raise TypeError(
                     f"__init__() got an unexpected keyword argument '{k}'"
                 )
@@ -14,7 +16,7 @@ def __init__(self, *args, **kwargs):
             post_init()
 
     def __repr__(self):
-        kwargs = {k: getattr(self, k) for k in cls.__annotations__}
+        kwargs = {k: getattr(self, k) for k in typing.get_type_hints(cls)}
         kwstr = ', '.join([f'{k}={v}' for k, v in kwargs.items()])
         return f'{cls.__name__}({kwstr})'
 
diff --git a/09-meta_dataclasses.py b/09-meta_dataclasses.py
index 6b72bcf..0f39ed1 100644
--- a/09-meta_dataclasses.py
+++ b/09-meta_dataclasses.py
@@ -1,5 +1,6 @@
 from dataclasses import dataclass
 from math import pi
+import typing
 
 
 class TypeChecker:
@@ -20,7 +21,7 @@ def __set__(self, instance, value):
 def typed_dataclass(cls):
     cls = dataclass(cls)
 
-    for var_name, var_type in cls.__annotations__.items():
+    for var_name, var_type in typing.get_type_hints(cls).items():
         class Checker(TypeChecker):
             required_type = var_type
 
diff --git a/11-ast.py b/11-ast.py
index 224f154..0b1800e 100644
--- a/11-ast.py
+++ b/11-ast.py
@@ -1,4 +1,5 @@
 import ast
+import typing
 
 # This could come from a variety of sources: not just text. For instance, we
 # could use inspect.get_source()
@@ -22,7 +23,7 @@ def __set__(self, instance, value):
 
 
 def type_check(cls):
-    for var_name, var_type in cls.__annotations__.items():
+    for var_name, var_type in typing.get_type_hints(cls).items():
         class Checker(TypeChecker):
             required_type = var_type
         setattr(cls, var_name, Checker(var_name))

From 41b3a554dd8ac70b4caf3f7923cd0ca1079784fa Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Mon, 23 Jul 2018 11:56:34 +0100
Subject: [PATCH 2/2] typing.get_type_hints handles missing __annotations__

https://github.com/python/cpython/blob/e019f98dc2fdddbee7990e518ead00de2245a0c8/Lib/typing.py#L967
---
 07-metaclasses.py      | 2 +-
 09-meta_dataclasses.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/07-metaclasses.py b/07-metaclasses.py
index 721ff1f..2fc11e0 100644
--- a/07-metaclasses.py
+++ b/07-metaclasses.py
@@ -33,7 +33,7 @@ def __new__(meta, name, bases, dct):
 
 
 class Base(metaclass=TypeCheckMeta):
-    __annotations__ = {}
+    pass
 
 
 class Point(Base):
diff --git a/09-meta_dataclasses.py b/09-meta_dataclasses.py
index 0f39ed1..bf6dd3b 100644
--- a/09-meta_dataclasses.py
+++ b/09-meta_dataclasses.py
@@ -36,7 +36,7 @@ def __new__(meta, name, bases, dct):
 
 
 class Base(metaclass=TypeCheckMeta):
-    __annotations__ = {}
+    pass
 
 
 class Point(Base):