Ensure that generated enum values have the correct base classesenum-fixes

Enum values should share the same base classes as their defining class.
If this is not the case it may lead to wrong inference results when an
enum member is used - e.g. for the following snippet:

class X(enum.IntEnum):
    one = 1

print([1, 2][X.one])

pylint will detect a "invalid-sequence-index" error as the __index__
method of X.one is not detected.

2 files changed, 35 insertions, 2 deletions

diff --git a/astroid/brain/py2stdlib.py b/astroid/brain/py2stdlib.py
index e63ea86..4231fe7 100644
--- a/astroid/brain/py2stdlib.py
+++ b/astroid/brain/py2stdlib.py
@@ -304,7 +304,7 @@ def infer_enum_class(node):
             for target in targets:
                 # Replace all the assignments with our mocked class.
                 classdef = dedent('''
-                class %(name)s(object):
+                class %(name)s(%(types)s):
                     @property
                     def value(self):
                         # Not the best return.
@@ -312,7 +312,7 @@ def infer_enum_class(node):
                     @property
                     def name(self):
                         return %(name)r
-                ''' % {'name': target.name})
+                ''' % {'name': target.name, 'types': ', '.join(node.basenames)})
                 fake = AstroidBuilder(MANAGER).string_build(classdef)[target.name]
                 fake.parent = target.parent
                 for method in node.mymethods():
diff --git a/astroid/tests/unittest_brain.py b/astroid/tests/unittest_brain.py
index 91a9a79..b0e0608 100644
--- a/astroid/tests/unittest_brain.py
+++ b/astroid/tests/unittest_brain.py
@@ -252,5 +252,38 @@ class EnumBrainTest(unittest.TestCase):
         meth = one.getattr('mymethod')[0]
         self.assertIsInstance(meth, astroid.Function)
 
+    def test_enum_multiple_base_classes(self):
+        module = AstroidBuilder().string_build(dedent("""
+        import enum
+
+        class Mixin:
+            pass
+
+        class MyEnum(Mixin, enum.Enum):
+            one = 1
+        """))
+        enum = next(module['MyEnum'].infer())
+        one = enum['one']
+
+        clazz = one.getattr('__class__')[0]
+        self.assertTrue(clazz.is_subtype_of('.Mixin'),
+                        'Enum instance should share base classes with generating class')
+
+    def test_int_enum(self):
+        module = AstroidBuilder().string_build(dedent("""
+        import enum
+
+        class MyEnum(enum.IntEnum):
+            one = 1
+        """))
+
+        enum = next(module['MyEnum'].infer())
+        one = enum['one']
+
+        clazz = one.getattr('__class__')[0]
+        int_type = '{}.{}'.format(bases.BUILTINS, 'int')
+        self.assertTrue(clazz.is_subtype_of(int_type),
+                        'IntEnum based enums should be a subtype of int')
+
 if __name__ == '__main__':
     unittest.main()