Need py__bool__ on generators as well as any other object.

jedi/evaluate/iterable.py

@@ -69,6 +69,9 @@ class GeneratorMixin(object):
         """
         return [self.iter_content()[index]]
 
+    def py__bool__(self):
+        return True
+
 
 class Generator(use_metaclass(CachedMetaClass, IterableWrapper, GeneratorMixin)):
     """Handling of `yield` functions."""
@@ -161,6 +164,9 @@ class ArrayMixin(object):
         scope = self._evaluator.execute(scope, (AlreadyEvaluated((self,)),))[0]
         return scope.names_dicts(search_global)
 
+    def py__bool__(self):
+        return None  # We don't know the length, because of appends.
+
 
 class ListComprehension(Comprehension, ArrayMixin):
     type = 'list'
@@ -203,9 +209,6 @@ class Array(IterableWrapper, ArrayMixin):
     def name(self):
         return helpers.FakeName(self.type, parent=self)
 
-    def py__bool__(self):
-        return None  # We don't know the length, because of appends.
-
     @memoize_default()
     def get_index_types(self, evaluator, index=()):
         """

test/completion/generators.py

@@ -24,6 +24,13 @@ next(gen_ret(1))
 #? []
 next(gen_ret())
 
+# generators evaluate to true if cast by bool.
+a = ''
+if gen_ret():
+    a = 3
+#? int()
+a
+
 
 # -----------------
 # generators should not be indexable