From f3ef06a7cb347ab7bd3cc2b0b3dcebe4f9ff36f9 Mon Sep 17 00:00:00 2001
From: Pablo Galindo <Pablogsal@gmail.com>
Date: Tue, 15 Oct 2019 12:40:02 +0100
Subject: [PATCH] bpo-38478: Correctly handle keyword argument with same name
 as positional-only parameter (GH-16800)

---
 Lib/inspect.py                                         |  2 +-
 Lib/test/test_inspect.py                               | 10 ++++++++++
 .../Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst   |  3 +++
 3 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst

diff --git a/Lib/inspect.py b/Lib/inspect.py
index c2a1ed4148e..3ff395ca333 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -2960,7 +2960,7 @@ class Signature:
                         arguments[param.name] = tuple(values)
                         break
 
-                    if param.name in kwargs:
+                    if param.name in kwargs and param.kind != _POSITIONAL_ONLY:
                         raise TypeError(
                             'multiple values for argument {arg!r}'.format(
                                 arg=param.name)) from None
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 9d28d5ad570..d95e742c8dd 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -3573,6 +3573,16 @@ class TestSignatureBind(unittest.TestCase):
         iterator = iter(range(5))
         self.assertEqual(self.call(setcomp_func, iterator), {0, 1, 4, 9, 16})
 
+    def test_signature_bind_posonly_kwargs(self):
+        def foo(bar, /, **kwargs):
+            return bar, kwargs.get(bar)
+
+        sig = inspect.signature(foo)
+        result = sig.bind("pos-only", bar="keyword")
+
+        self.assertEqual(result.kwargs, {"bar": "keyword"})
+        self.assertIn(("bar", "pos-only"), result.arguments.items())
+
 
 class TestBoundArguments(unittest.TestCase):
     def test_signature_bound_arguments_unhashable(self):
diff --git a/Misc/NEWS.d/next/Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst b/Misc/NEWS.d/next/Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst
new file mode 100644
index 00000000000..b19fa23639d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst
@@ -0,0 +1,3 @@
+Fixed a bug in :meth:`inspect.signature.bind` that was causing it to fail
+when handling a keyword argument with same name as positional-only parameter.
+Patch by Pablo Galindo.