honor dict key / value iteration order (#872)

pyflakes/checker.py

diff --git a/pyflakes/checker.py b/pyflakes/checker.py
index 5dc3251..4c05298 100644
--- a/pyflakes/checker.py
+++ b/pyflakes/checker.py
@@ -16,6 +16,7 @@
 import string
 import sys
 import warnings
+from collections.abc import Iterable
 
 from pyflakes import messages
 
@@ -169,6 +170,10 @@
                     yield item
 
 
+def iter_dict_children(node: ast.Dict) -> Iterable[tuple[ast.AST, ast.AST]]:
+    return zip(node.keys, node.values)
+
+
 def convert_to_value(item):
     if isinstance(item, ast.Constant):
         return item.value
@@ -1607,8 +1612,9 @@
 
             # TypedDict("a", {"a": int})
             if len(node.args) > 1 and isinstance(node.args[1], ast.Dict):
-                _non_annotations(node.args[1].keys)
-                _annotations(node.args[1].values)
+                for k, v in iter_dict_children(node.args[1]):
+                    _non_annotation(k)
+                    _annotation(v)
             _non_annotations(node.args[2:])
 
             # TypedDict("a", a=int)
@@ -1861,7 +1867,10 @@
                             key_node,
                             key,
                         )
-        self.handleChildren(node)
+
+        for k, v in iter_dict_children(node):
+            self.handleNode(k, node)
+            self.handleNode(v, node)
 
     def IF(self, node):
         if isinstance(node.test, ast.Tuple) and node.test.elts != []:

pyflakes/test/test_other.py

diff --git a/pyflakes/test/test_other.py b/pyflakes/test/test_other.py
index 77f7606..9c6c5ba 100644
--- a/pyflakes/test/test_other.py
+++ b/pyflakes/test/test_other.py
@@ -1810,6 +1810,15 @@
             print(z)
         ''')
 
+    def test_dict_key_value_ordering_assignment_expressions(self):
+        # https://docs.python.org/3/reference/expressions.html#dictionary-displays
+        self.flakes('''
+        {
+            '1': (y := 2),
+            y: '3',
+        }
+        ''')
+
     @skipIf(version_info < (3, 15), 'new in Python 3.15')
     def test_reassigned_in_comprehension_unpacking(self):
         self.flakes('''

pyflakes/test/test_type_annotations.py

diff --git a/pyflakes/test/test_type_annotations.py b/pyflakes/test/test_type_annotations.py
index b86bdca..4416a2a 100644
--- a/pyflakes/test/test_type_annotations.py
+++ b/pyflakes/test/test_type_annotations.py
@@ -788,6 +788,13 @@
             TypedDict("U", x="T")
             ''')
 
+    def test_typeddict_key_value_ordering(self):
+        self.flakes("""
+        from typing import TypedDict
+        from u import V
+        TypedDict("TD", {"k": (y := "V"), y: "V"})
+        """)
+
     def test_namedtypes_classes(self):
         self.flakes("""
             from typing import TypedDict, NamedTuple