From eda6b5ed229aeafa95bea759efb3c9876ee1be72 Mon Sep 17 00:00:00 2001
From: Claude Agent <agent@example.com>
Date: Tue, 19 May 2026 16:03:56 +0000
Subject: [PATCH] Fix false positive "Expected TypedDict key to be string
 literal" for Union[TypedDict, dict[int, float]]

When matching a dict literal against a union type containing both a TypedDict and a
plain dict (e.g. `Union[Foo, dict[int, float]]`), `match_typeddict_call_with_dict`
was emitting an error while probing whether the literal matched the TypedDict alternative.
Suppress errors during matching so they are only reported during actual type checking.

Fixes #21510
---
 mypy/checkexpr.py                   |  3 ++-
 test-data/unit/check-typeddict.test | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index c968e5cc6923b..882d748afaead 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -932,7 +932,8 @@ def match_typeddict_call_with_dict(
         kwargs: list[tuple[Expression | None, Expression]],
         context: Context,
     ) -> bool:
-        result = self.validate_typeddict_kwargs(kwargs=kwargs, callee=callee)
+        with self.msg.filter_errors():
+            result = self.validate_typeddict_kwargs(kwargs=kwargs, callee=callee)
         if result is not None:
             validated_kwargs, _ = result
             return callee.required_keys <= set(validated_kwargs.keys()) <= set(callee.items.keys())
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index c74ae96d7763e..17a1fea22ef04 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -941,6 +941,18 @@ c: Union[A, B] = {'@type': 'a-type', 'value': 'Test'}  # E: Type of TypedDict is
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
 
+[case testTypedDictUnionWithNonTypedDictLiteralKey]
+from typing import Union, TypedDict
+
+class Foo(TypedDict):
+    some: str
+    name: str
+
+baz: Union[Foo, dict[int, float]] = {1: 5.2}
+baz2: Union[Foo, dict[int, float]] = {'some': 'x', 'name': 'y'}
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
 -- Use dict literals
 
 [case testTypedDictDictLiterals]