Add support for PEP 0526.

This makes it possible to assign variables like

    asdf: typing.List[int] = []

jedi/evaluate/__init__.py

@@ -77,6 +77,7 @@ from jedi.evaluate import compiled
 from jedi.evaluate import precedence
 from jedi.evaluate import param
 from jedi.evaluate import helpers
+from jedi.evaluate import pep0484
 from jedi.evaluate.filters import TreeNameDefinition, ParamName
 from jedi.evaluate.instance import AnonymousInstance, BoundMethod
 
@@ -152,7 +153,7 @@ class Evaluator(object):
             types = finder.check_tuple_assignments(self, types, seek_name)
 
         first_operation = stmt.first_operation()
-        if first_operation not in ('=', None):
+        if first_operation not in ('=', None) and first_operation.type == 'operator':
             # `=` is always the last character in aug assignments -> -1
             operator = copy.copy(first_operation)
             operator.value = operator.value[:-1]
@@ -315,6 +316,10 @@ class Evaluator(object):
             types = types
         elif element.type == 'eval_input':
             types = self._eval_element_not_cached(context, element.children[0])
+        elif element.type == 'annassign':
+            print(element.children[1])
+            types = pep0484._evaluate_for_annotation(context, element.children[1])
+            print('xxx')
         else:
             types = precedence.calculate_children(self, context, element.children)
         debug.dbg('eval_element result %s', types)

jedi/parser/tree.py

@@ -1531,9 +1531,14 @@ class ExprStmt(BaseNode, DocstringMixin):
     __slots__ = ()
 
     def get_defined_names(self):
-        return list(chain.from_iterable(_defined_names(self.children[i])
+        names = []
+        if self.children[1].type == 'annassign':
+            names = _defined_names(self.children[0])
+        return list(chain.from_iterable(
+            _defined_names(self.children[i])
             for i in range(0, len(self.children) - 2, 2)
-                                        if '=' in self.children[i + 1].value))
+            if '=' in self.children[i + 1].value)
+        ) + names
 
     def get_rhs(self):
         """Returns the right-hand-side of the equals."""

test/completion/pep0526_variables.py

@@ -0,0 +1,22 @@
+"""
+PEP 526 introduced a new way of using type annotations on variables. It was
+introduced in Python 3.6.
+"""
+# python >= 3.6
+
+import typing
+
+asdf = ''
+asdf: int
+# This is not necessarily correct, but for now this is ok (at least no error).
+#? int()
+asdf
+
+
+direct: int = NOT_DEFINED
+#? int()
+direct
+
+with_typing_module: typing.List[float] = NOT_DEFINED
+#? float()
+with_typing_module[0]