Fix crash when handling generator inside with context

3 files changed, 19 insertions, 3 deletions

diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index a0f1e5e..04b2c9d 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -29,6 +29,7 @@ from astroid import (
     MroError, SuperError, YES, Instance
 )
 from astroid.bases import BUILTINS
+from astroid.bases import NodeNG
 from astroid import objects
 from astroid import helpers
 import six
@@ -48,11 +49,11 @@ _ZOPE_DEPRECATED = (
 
 def _unflatten(iterable):
     for elem in iterable:
-        elem = elem[0]
-        if isinstance(elem, collections.Sequence):
+        if (isinstance(elem, collections.Sequence) and
+            not isinstance(elem, basestring)):
             for subelem in _unflatten(elem):
                 yield subelem
-        else:
+        elif isinstance(elem, NodeNG):
             yield elem
 
 
diff --git a/pylint/test/functional/with_using_generator.py b/pylint/test/functional/with_using_generator.py
new file mode 100644
index 0000000..25c6b37
--- /dev/null
+++ b/pylint/test/functional/with_using_generator.py
@@ -0,0 +1,14 @@
+""" Testing with statements that use generators. This should not crash. """
+
+class Base(object):
+    """ Base class. """
+    val = 0
+
+    def gen(self):
+        """ A generator. """
+        yield self.val
+
+    def fun(self):
+        """ With statement using a generator. """
+        with self.gen():  # [not-context-manager]
+            pass
diff --git a/pylint/test/functional/with_using_generator.txt b/pylint/test/functional/with_using_generator.txt
new file mode 100644
index 0000000..276b05c
--- /dev/null
+++ b/pylint/test/functional/with_using_generator.txt
@@ -0,0 +1 @@
+not-context-manager:13:Base.fun:Context manager 'generator' doesn't implement __enter__ and __exit__.