make generator comprehensions work

jedi/evaluate/__init__.py

@@ -170,15 +170,22 @@ class Evaluator(object):
                 return self._eval_precedence(el)
             else:
                 # normal element, no operators
-                return self._eval_statement_element(el)
+                return self.eval_statement_element(el)
 
     def _eval_precedence(self, _precedence):
         left = self.process_precedence_element(_precedence.left)
         right = self.process_precedence_element(_precedence.right)
         return precedence.calculate(self, left, _precedence.operator, right)
 
-    def _eval_statement_element(self, element):
+    def eval_statement_element(self, element):
         if pr.Array.is_type(element, pr.Array.NOARRAY):
+            try:
+                lst_cmp = element[0].expression_list()[0]
+            except IndexError:
+                pass
+            else:
+                if isinstance(lst_cmp, pr.ListComprehension):
+                    return [iterable.GeneratorComprehension(self, lst_cmp)]
             r = list(itertools.chain.from_iterable(self.eval_statement(s)
                                                    for s in element))
             call_path = element.generate_call_path()

jedi/evaluate/finder.py

@@ -471,6 +471,7 @@ def get_names_of_scope(evaluator, scope, position=None, star_search=True, includ
     """
     if isinstance(scope, iterable.ListComprehensionFlow):
         position = scope.list_comprehension.parent.start_pos
+
     in_func_scope = scope
     non_flow = scope.get_parent_until(pr.Flow, reverse=True)
     while scope:

jedi/evaluate/iterable.py

@@ -66,6 +66,13 @@ class Generator(use_metaclass(CachedMetaClass, pr.Base)):
         analysis.add(self._evaluator, 'type-error-generator', index_array)
         return []
 
+    def get_exact_index_types(self, index):
+        """
+        Exact lookups are used for tuple lookups, which are perfectly fine if
+        used with generators.
+        """
+        return [self.iter_content()[index]]
+
     def __getattr__(self, name):
         if name not in ['start_pos', 'end_pos', 'parent', 'get_imports',
                         'asserts', 'doc', 'docstr', 'get_parent_until',
@@ -91,6 +98,15 @@ class GeneratorMethod(object):
         return getattr(self._builtin_func, name)
 
 
+class GeneratorComprehension(Generator):
+    def __init__(self, evaluator, comprehension):
+        super(GeneratorComprehension, self).__init__(evaluator, comprehension, None)
+        self.comprehension = comprehension
+
+    def iter_content(self):
+        return self._evaluator.eval_statement_element(self.comprehension)
+
+
 class Array(use_metaclass(CachedMetaClass, pr.Base)):
     """
     Used as a mirror to pr.Array, if needed. It defines some getter

test/completion/basic.py

@@ -168,6 +168,15 @@ a[0]
 #? int()
 a[0][0]
 
+# -----------------
+# generator comprehensions
+# -----------------
+
+left, right = (i for i in (1, ''))
+
+#? int()
+left
+
 # -----------------
 # ternary operator
 # -----------------