Add PEP 526 AutoCompletion (#1102)

By following instructions similar to this link:
davidhalter/jedi@3f09f3a

It is now possible to give autocompletion for variable declared in the following fashion:

test: str = "PEP 562 Support"

Related issues can be found here:
https://github.com/DonJayamanne/pythonVSCode/issues/1101

Author: Costa Huang

pythonFiles/preview/jedi/evaluate/__init__.py

@@ -162,7 +162,7 @@ def eval_statement(self, stmt, seek_name=None):
             types = finder.check_tuple_assignments(self, types, seek_name)
 
         first_operation = stmt.first_operation()
-        if first_operation not in ('=', None) and not isinstance(stmt, er.InstanceElement):  # TODO don't check for this.
+        if first_operation not in ('=', None) and not isinstance(stmt, er.InstanceElement) and first_operation.type == 'operator':  # TODO don't check for this.
             # `=` is always the last character in aug assignments -> -1
             operator = copy.copy(first_operation)
             operator.value = operator.value[:-1]
@@ -327,6 +327,8 @@ def _eval_element_not_cached(self, element):
             types = types
         elif element.type == 'eval_input':
             types = self._eval_element_not_cached(element.children[0])
+        elif element.type == 'annassign':
+            types = self.eval_element(element.children[1])
         else:
             types = precedence.calculate_children(self, element.children)
         debug.dbg('eval_element result %s', types)

pythonFiles/preview/jedi/parser/tree.py

@@ -1522,9 +1522,14 @@ class ExprStmt(BaseNode, DocstringMixin):
     __slots__ = ()
 
     def get_defined_names(self):
-        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))
+        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)  
+        ) + names
 
     def get_rhs(self):
         """Returns the right-hand-side of the equals."""