From e422e53042ada656f7a485f2d053dc1885193026 Mon Sep 17 00:00:00 2001
From: Anthony Sottile <asottile@umich.edu>
Date: Mon, 12 Aug 2019 06:00:58 -0700
Subject: Add support for PEP 572 assignment expressions (#457)

---
 pyflakes/checker.py         | 2 +-
 pyflakes/test/test_other.py | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/pyflakes/checker.py b/pyflakes/checker.py
index f2e579f..3ed398d 100644
--- a/pyflakes/checker.py
+++ b/pyflakes/checker.py
@@ -1329,7 +1329,7 @@ class Checker(object):
     # "expr" type nodes
     BOOLOP = UNARYOP = IFEXP = SET = \
         REPR = ATTRIBUTE = SUBSCRIPT = \
-        STARRED = NAMECONSTANT = handleChildren
+        STARRED = NAMECONSTANT = NAMEDEXPR = handleChildren
 
     def _handle_string_dot_format(self, node):
         try:
diff --git a/pyflakes/test/test_other.py b/pyflakes/test/test_other.py
index 775fdde..df2f790 100644
--- a/pyflakes/test/test_other.py
+++ b/pyflakes/test/test_other.py
@@ -1754,6 +1754,15 @@ class TestUnusedAssignment(TestCase):
         print(f'\x7b4*baz\N{RIGHT CURLY BRACKET}')
         ''')
 
+    @skipIf(version_info < (3, 8), 'new in Python 3.8')
+    def test_assign_expr(self):
+        """Test PEP 572 assignment expressions are treated as usage / write."""
+        self.flakes('''
+        from foo import y
+        print(x := y)
+        print(x)
+        ''')
+
 
 class TestStringFormatting(TestCase):
 
-- 
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