Some improvements towards iterators.

jedi/evaluate/__init__.py

@@ -152,8 +152,7 @@ class Evaluator(object):
             operator = copy.copy(first_operation)
             operator.value = operator.value[:-1]
             name = str(stmt.get_defined_names()[0])
-            parent = self.wrap(stmt.get_parent_scope())
-            left = self.find_types(parent, name, stmt.start_pos, search_global=True)
+            left = self.find_types(context, name, stmt.start_pos, search_global=True)
 
             for_stmt = stmt.get_parent_until(tree.ForStmt)
             if isinstance(for_stmt, tree.ForStmt) and types \
@@ -351,7 +350,7 @@ class Evaluator(object):
             elif c[0] == '(' and not len(c) == 2 \
                     and not(tree.is_node(c[1], 'testlist_comp')
                             and len(c[1].children) > 1):
-                return self.eval_element(c[1])
+                return self.eval_element(context, c[1])
 
             try:
                 comp_for = c[1].children[1]

jedi/evaluate/compiled/__init__.py

@@ -13,7 +13,7 @@ from jedi.cache import underscore_memoization, memoize_method
 from jedi.parser.tree import Param, Operator
 from jedi.evaluate.helpers import FakeName
 from jedi.evaluate.filters import AbstractFilter, AbstractNameDefinition
-from jedi.evaluate.context import Context
+from jedi.evaluate.context import Context, LazyKnownContext
 from . import fake
 
 
@@ -202,7 +202,7 @@ class CompiledObject(Context):
             return
 
         for part in self.obj:
-            yield set([create(self.evaluator, part)])
+            yield LazyKnownContext(create(self.evaluator, part))
 
     @property
     def name(self):

jedi/evaluate/finder.py

@@ -370,7 +370,7 @@ def _name_to_types(evaluator, context, name, scope):
     elif node.isinstance(tree.ExprStmt):
         types = _remove_statements(evaluator, context, node, name)
     elif node.isinstance(tree.WithStmt):
-        types = evaluator.eval_element(node.node_from_name(name))
+        types = context.eval_node(node.node_from_name(name))
     elif isinstance(node, tree.Import):
         types = imports.ImportWrapper(context, name).follow()
     elif node.type in ('funcdef', 'classdef'):

jedi/evaluate/instance.py

@@ -1,10 +1,11 @@
 from abc import abstractproperty
 
+from jedi._compatibility import is_py3
 from jedi.common import unite
 from jedi import debug
 from jedi.evaluate import compiled
 from jedi.evaluate import filters
-from jedi.evaluate.context import Context, LazyKnownContext
+from jedi.evaluate.context import Context, LazyKnownContext, get_merged_lazy_context
 from jedi.evaluate.cache import memoize_default
 from jedi.cache import memoize_method
 from jedi.evaluate import representation as er
@@ -117,24 +118,24 @@ class AbstractInstanceContext(Context):
             return unite(name.execute_evaluated(index_obj) for name in names)
 
     def py__iter__(self):
-        try:
-            method = self.get_subscope_by_name('__iter__')
-        except KeyError:
+        iter_slot_names = self.get_function_slot_names('__iter__')
+        if not iter_slot_names:
             debug.warning('No __iter__ on %s.' % self)
             return
-        else:
-            iters = self.evaluator.execute(method)
-            for generator in iters:
-                if isinstance(generator, Instance):
+
+        for generator in self.execute_function_slots(iter_slot_names):
+            if isinstance(generator, AbstractInstanceContext):
                 # `__next__` logic.
                 name = '__next__' if is_py3 else 'next'
                 try:
-                        yield generator.execute_subscope_by_name(name)
+                    yield get_merged_lazy_context(
+                        generator.execute_subscope_by_name(name)
+                    )
                 except KeyError:
                     debug.warning('Instance has no __next__ function in %s.', generator)
             else:
-                    for typ in generator.py__iter__():
-                        yield typ
+                for lazy_context in generator.py__iter__():
+                    yield lazy_context
 
     @abstractproperty
     def name(self):

jedi/evaluate/iterable.py

@@ -611,8 +611,10 @@ def py__iter__(evaluator, types, node=None):
         else:
             type_iters.append(iter_method())
 
-    for lazy_contexts in zip_longest(*type_iters, fillvalue=set()):
-        yield context.get_merged_lazy_context(lazy_contexts)
+    for lazy_contexts in zip_longest(*type_iters, fillvalue=None):
+        yield context.get_merged_lazy_context(
+            [l for l in lazy_contexts if l is not None]
+        )
 
 
 def py__iter__types(evaluator, types, node=None):