Make duplicated_kwargs a public API.

2 files changed, 8 insertions, 4 deletions

diff --git a/astroid/arguments.py b/astroid/arguments.py
index bdce172..5670fa8 100644
--- a/astroid/arguments.py
+++ b/astroid/arguments.py
@@ -38,8 +38,7 @@ class CallSite(object):
     def __init__(self, callcontext):
         args = callcontext.args
         keywords = callcontext.keywords
-
-        self._duplicated_kwargs = {}
+        self.duplicated_keywords = set()
         self._unpacked_args = self._unpack_args(args)
         self._unpacked_kwargs = self._unpack_keywords(keywords)
 
@@ -111,7 +110,7 @@ class CallSite(object):
                     if dict_key.value in values:
                         # The name is already in the dictionary
                         values[dict_key.value] = util.YES
-                        self._duplicated_kwargs[dict_key.value] = True
+                        self.duplicated_keywords.add(dict_key.value)
                         continue
                     values[dict_key.value] = dict_value
             else:
@@ -143,7 +142,7 @@ class CallSite(object):
 
     def infer_argument(self, funcnode, name, context):
         """infer a function argument value according to the call context"""
-        if name in self._duplicated_kwargs:
+        if name in self.duplicated_keywords:
             raise exceptions.InferenceError(name)
 
         # Look into the keywords first, maybe it's already there.
diff --git a/astroid/tests/unittest_inference.py b/astroid/tests/unittest_inference.py
index 5fac5f9..ed13fc2 100644
--- a/astroid/tests/unittest_inference.py
+++ b/astroid/tests/unittest_inference.py
@@ -3766,6 +3766,11 @@ class CallSiteTest(unittest.TestCase):
         ]
         self._test_call_site_valid_arguments(values, invalid=False)
 
+    def test_duplicated_keyword_arguments(self):
+        ast_node = test_utils.extract_node('f(f=24, **{"f": 25})')
+        site = self._call_site_from_call(ast_node)
+        self.assertIn('f', site.duplicated_keywords)
+
 
 if __name__ == '__main__':
     unittest.main()