diff --git a/conformance/results/mypy/narrowing_typeis.toml b/conformance/results/mypy/narrowing_typeis.toml
index 5000a5bf..cdb53c5e 100644
--- a/conformance/results/mypy/narrowing_typeis.toml
+++ b/conformance/results/mypy/narrowing_typeis.toml
@@ -1,15 +1,15 @@
 conformant = "Pass"
 output = """
-narrowing_typeis.py:105: error: "TypeIs" functions must have a positional argument  [valid-type]
 narrowing_typeis.py:110: error: "TypeIs" functions must have a positional argument  [valid-type]
-narrowing_typeis.py:132: error: Argument 1 to "takes_callable_str" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], str]"  [arg-type]
-narrowing_typeis.py:152: error: Argument 1 to "takes_callable_str_proto" has incompatible type "Callable[[object], TypeIs[int]]"; expected "CallableStrProto"  [arg-type]
-narrowing_typeis.py:152: note: "CallableStrProto.__call__" has type "def __call__(self, val: object) -> str"
-narrowing_typeis.py:169: error: Argument 1 to "takes_typeguard" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], TypeGuard[int]]"  [arg-type]
-narrowing_typeis.py:170: error: Argument 1 to "takes_typeis" has incompatible type "Callable[[object], TypeGuard[int]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
-narrowing_typeis.py:191: error: Argument 1 to "takes_int_typeis" has incompatible type "Callable[[object], TypeIs[bool]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
-narrowing_typeis.py:195: error: Narrowed type "str" is not a subtype of input type "int"  [narrowed-type-not-subtype]
-narrowing_typeis.py:199: error: Narrowed type "list[int]" is not a subtype of input type "list[object]"  [narrowed-type-not-subtype]
+narrowing_typeis.py:115: error: "TypeIs" functions must have a positional argument  [valid-type]
+narrowing_typeis.py:137: error: Argument 1 to "takes_callable_str" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], str]"  [arg-type]
+narrowing_typeis.py:157: error: Argument 1 to "takes_callable_str_proto" has incompatible type "Callable[[object], TypeIs[int]]"; expected "CallableStrProto"  [arg-type]
+narrowing_typeis.py:157: note: "CallableStrProto.__call__" has type "def __call__(self, val: object) -> str"
+narrowing_typeis.py:174: error: Argument 1 to "takes_typeguard" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], TypeGuard[int]]"  [arg-type]
+narrowing_typeis.py:175: error: Argument 1 to "takes_typeis" has incompatible type "Callable[[object], TypeGuard[int]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
+narrowing_typeis.py:196: error: Argument 1 to "takes_int_typeis" has incompatible type "Callable[[object], TypeIs[bool]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
+narrowing_typeis.py:200: error: Narrowed type "str" is not a subtype of input type "int"  [narrowed-type-not-subtype]
+narrowing_typeis.py:204: error: Narrowed type "list[int]" is not a subtype of input type "list[object]"  [narrowed-type-not-subtype]
 """
 conformance_automated = "Pass"
 errors_diff = """
diff --git a/conformance/results/pyrefly/narrowing_typeis.toml b/conformance/results/pyrefly/narrowing_typeis.toml
index 8ebf9e4a..008c5b41 100644
--- a/conformance/results/pyrefly/narrowing_typeis.toml
+++ b/conformance/results/pyrefly/narrowing_typeis.toml
@@ -3,13 +3,13 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-ERROR narrowing_typeis.py:105:9-13: Type guard functions must accept at least one positional argument [bad-function-definition]
 ERROR narrowing_typeis.py:110:9-13: Type guard functions must accept at least one positional argument [bad-function-definition]
-ERROR narrowing_typeis.py:132:20-36: Argument `(val: object) -> TypeIs[int]` is not assignable to parameter `f` with type `(object) -> str` in function `takes_callable_str` [bad-argument-type]
-ERROR narrowing_typeis.py:152:26-42: Argument `(val: object) -> TypeIs[int]` is not assignable to parameter `f` with type `CallableStrProto` in function `takes_callable_str_proto` [bad-argument-type]
-ERROR narrowing_typeis.py:169:17-30: Argument `(val: object) -> TypeIs[int]` is not assignable to parameter `f` with type `(object) -> TypeGuard[int]` in function `takes_typeguard` [bad-argument-type]
-ERROR narrowing_typeis.py:170:14-30: Argument `(val: object) -> TypeGuard[int]` is not assignable to parameter `f` with type `(object) -> TypeIs[int]` in function `takes_typeis` [bad-argument-type]
-ERROR narrowing_typeis.py:191:18-29: Argument `(val: object) -> TypeIs[bool]` is not assignable to parameter `f` with type `(object) -> TypeIs[int]` in function `takes_int_typeis` [bad-argument-type]
-ERROR narrowing_typeis.py:195:5-15: Return type `str` must be assignable to the first argument type `int` [bad-function-definition]
-ERROR narrowing_typeis.py:199:5-24: Return type `list[int]` must be assignable to the first argument type `list[object]` [bad-function-definition]
+ERROR narrowing_typeis.py:115:9-13: Type guard functions must accept at least one positional argument [bad-function-definition]
+ERROR narrowing_typeis.py:137:20-36: Argument `(val: object) -> TypeIs[int]` is not assignable to parameter `f` with type `(object) -> str` in function `takes_callable_str` [bad-argument-type]
+ERROR narrowing_typeis.py:157:26-42: Argument `(val: object) -> TypeIs[int]` is not assignable to parameter `f` with type `CallableStrProto` in function `takes_callable_str_proto` [bad-argument-type]
+ERROR narrowing_typeis.py:174:17-30: Argument `(val: object) -> TypeIs[int]` is not assignable to parameter `f` with type `(object) -> TypeGuard[int]` in function `takes_typeguard` [bad-argument-type]
+ERROR narrowing_typeis.py:175:14-30: Argument `(val: object) -> TypeGuard[int]` is not assignable to parameter `f` with type `(object) -> TypeIs[int]` in function `takes_typeis` [bad-argument-type]
+ERROR narrowing_typeis.py:196:18-29: Argument `(val: object) -> TypeIs[bool]` is not assignable to parameter `f` with type `(object) -> TypeIs[int]` in function `takes_int_typeis` [bad-argument-type]
+ERROR narrowing_typeis.py:200:5-15: Return type `str` must be assignable to the first argument type `int` [bad-function-definition]
+ERROR narrowing_typeis.py:204:5-24: Return type `list[int]` must be assignable to the first argument type `list[object]` [bad-function-definition]
 """
diff --git a/conformance/results/pyright/narrowing_typeis.toml b/conformance/results/pyright/narrowing_typeis.toml
index ca6a42a9..327ec9f1 100644
--- a/conformance/results/pyright/narrowing_typeis.toml
+++ b/conformance/results/pyright/narrowing_typeis.toml
@@ -3,34 +3,34 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-narrowing_typeis.py:105:9 - error: User-defined type guard functions and methods must have at least one input parameter (reportGeneralTypeIssues)
 narrowing_typeis.py:110:9 - error: User-defined type guard functions and methods must have at least one input parameter (reportGeneralTypeIssues)
-narrowing_typeis.py:132:20 - error: Argument of type "(val: object) -> TypeIs[int]" cannot be assigned to parameter "f" of type "(object) -> str" in function "takes_callable_str"
+narrowing_typeis.py:115:9 - error: User-defined type guard functions and methods must have at least one input parameter (reportGeneralTypeIssues)
+narrowing_typeis.py:137:20 - error: Argument of type "(val: object) -> TypeIs[int]" cannot be assigned to parameter "f" of type "(object) -> str" in function "takes_callable_str"
   Type "(val: object) -> TypeIs[int]" is not assignable to type "(object) -> str"
     Function return type "TypeIs[int]" is incompatible with type "str"
       "TypeIs[int]" is not assignable to "str"
       "bool" is not assignable to "str" (reportArgumentType)
-narrowing_typeis.py:152:26 - error: Argument of type "(val: object) -> TypeIs[int]" cannot be assigned to parameter "f" of type "CallableStrProto" in function "takes_callable_str_proto"
+narrowing_typeis.py:157:26 - error: Argument of type "(val: object) -> TypeIs[int]" cannot be assigned to parameter "f" of type "CallableStrProto" in function "takes_callable_str_proto"
   Type "(val: object) -> TypeIs[int]" is not assignable to type "(val: object) -> str"
     Function return type "TypeIs[int]" is incompatible with type "str"
       "TypeIs[int]" is not assignable to "str"
       "bool" is not assignable to "str" (reportArgumentType)
-narrowing_typeis.py:169:17 - error: Argument of type "(val: object) -> TypeIs[int]" cannot be assigned to parameter "f" of type "(object) -> TypeGuard[int]" in function "takes_typeguard"
+narrowing_typeis.py:174:17 - error: Argument of type "(val: object) -> TypeIs[int]" cannot be assigned to parameter "f" of type "(object) -> TypeGuard[int]" in function "takes_typeguard"
   Type "(val: object) -> TypeIs[int]" is not assignable to type "(object) -> TypeGuard[int]"
     Function return type "TypeIs[int]" is incompatible with type "TypeGuard[int]"
       "TypeIs[int]" is not assignable to "TypeGuard[int]"
       "bool" is not assignable to "TypeGuard[int]" (reportArgumentType)
-narrowing_typeis.py:170:14 - error: Argument of type "(val: object) -> TypeGuard[int]" cannot be assigned to parameter "f" of type "(object) -> TypeIs[int]" in function "takes_typeis"
+narrowing_typeis.py:175:14 - error: Argument of type "(val: object) -> TypeGuard[int]" cannot be assigned to parameter "f" of type "(object) -> TypeIs[int]" in function "takes_typeis"
   Type "(val: object) -> TypeGuard[int]" is not assignable to type "(object) -> TypeIs[int]"
     Function return type "TypeGuard[int]" is incompatible with type "TypeIs[int]"
       "TypeGuard[int]" is not assignable to "TypeIs[int]"
       "bool" is not assignable to "TypeIs[int]" (reportArgumentType)
-narrowing_typeis.py:191:18 - error: Argument of type "(val: object) -> TypeIs[bool]" cannot be assigned to parameter "f" of type "(object) -> TypeIs[int]" in function "takes_int_typeis"
+narrowing_typeis.py:196:18 - error: Argument of type "(val: object) -> TypeIs[bool]" cannot be assigned to parameter "f" of type "(object) -> TypeIs[int]" in function "takes_int_typeis"
   Type "(val: object) -> TypeIs[bool]" is not assignable to type "(object) -> TypeIs[int]"
     Function return type "TypeIs[bool]" is incompatible with type "TypeIs[int]"
       "TypeIs[bool]" is not assignable to "TypeIs[int]"
         Type parameter "T@TypeIs" is invariant, but "bool" is not the same as "int"
       "bool" is not assignable to "TypeIs[int]" (reportArgumentType)
-narrowing_typeis.py:195:27 - error: Return type of TypeIs ("str") is not consistent with value parameter type ("int") (reportGeneralTypeIssues)
-narrowing_typeis.py:199:45 - error: Return type of TypeIs ("list[int]") is not consistent with value parameter type ("list[object]") (reportGeneralTypeIssues)
+narrowing_typeis.py:200:27 - error: Return type of TypeIs ("str") is not consistent with value parameter type ("int") (reportGeneralTypeIssues)
+narrowing_typeis.py:204:45 - error: Return type of TypeIs ("list[int]") is not consistent with value parameter type ("list[object]") (reportGeneralTypeIssues)
 """
diff --git a/conformance/results/ty/narrowing_typeis.toml b/conformance/results/ty/narrowing_typeis.toml
index 5cabfbbc..7abfa5ba 100644
--- a/conformance/results/ty/narrowing_typeis.toml
+++ b/conformance/results/ty/narrowing_typeis.toml
@@ -8,13 +8,13 @@ Line 35: Unexpected errors ['narrowing_typeis.py:35:18: error[invalid-assignment
 """
 output = """
 narrowing_typeis.py:35:18: error[invalid-assignment] Object of type `object` is not assignable to `int`
-narrowing_typeis.py:105:23: error[invalid-type-guard-definition] `TypeIs` function must have a parameter to narrow
-narrowing_typeis.py:110:22: error[invalid-type-guard-definition] `TypeIs` function must have a parameter to narrow
-narrowing_typeis.py:132:20: error[invalid-argument-type] Argument to function `takes_callable_str` is incorrect: Expected `(object, /) -> str`, found `def simple_typeguard(val: object) -> TypeIs[int]`
-narrowing_typeis.py:152:26: error[invalid-argument-type] Argument to function `takes_callable_str_proto` is incorrect: Expected `CallableStrProto`, found `def simple_typeguard(val: object) -> TypeIs[int]`
-narrowing_typeis.py:169:17: error[invalid-argument-type] Argument to function `takes_typeguard` is incorrect: Expected `(object, /) -> TypeGuard[int]`, found `def is_int_typeis(val: object) -> TypeIs[int]`
-narrowing_typeis.py:170:14: error[invalid-argument-type] Argument to function `takes_typeis` is incorrect: Expected `(object, /) -> TypeIs[int]`, found `def is_int_typeguard(val: object) -> TypeGuard[int]`
-narrowing_typeis.py:191:18: error[invalid-argument-type] Argument to function `takes_int_typeis` is incorrect: Expected `(object, /) -> TypeIs[int]`, found `def bool_typeis(val: object) -> TypeIs[bool]`
-narrowing_typeis.py:195:27: error[invalid-type-guard-definition] Narrowed type `str` is not assignable to the declared parameter type `int`
-narrowing_typeis.py:199:45: error[invalid-type-guard-definition] Narrowed type `list[int]` is not assignable to the declared parameter type `list[object]`
+narrowing_typeis.py:110:23: error[invalid-type-guard-definition] `TypeIs` function must have a parameter to narrow
+narrowing_typeis.py:115:22: error[invalid-type-guard-definition] `TypeIs` function must have a parameter to narrow
+narrowing_typeis.py:137:20: error[invalid-argument-type] Argument to function `takes_callable_str` is incorrect: Expected `(object, /) -> str`, found `def simple_typeguard(val: object) -> TypeIs[int]`
+narrowing_typeis.py:157:26: error[invalid-argument-type] Argument to function `takes_callable_str_proto` is incorrect: Expected `CallableStrProto`, found `def simple_typeguard(val: object) -> TypeIs[int]`
+narrowing_typeis.py:174:17: error[invalid-argument-type] Argument to function `takes_typeguard` is incorrect: Expected `(object, /) -> TypeGuard[int]`, found `def is_int_typeis(val: object) -> TypeIs[int]`
+narrowing_typeis.py:175:14: error[invalid-argument-type] Argument to function `takes_typeis` is incorrect: Expected `(object, /) -> TypeIs[int]`, found `def is_int_typeguard(val: object) -> TypeGuard[int]`
+narrowing_typeis.py:196:18: error[invalid-argument-type] Argument to function `takes_int_typeis` is incorrect: Expected `(object, /) -> TypeIs[int]`, found `def bool_typeis(val: object) -> TypeIs[bool]`
+narrowing_typeis.py:200:27: error[invalid-type-guard-definition] Narrowed type `str` is not assignable to the declared parameter type `int`
+narrowing_typeis.py:204:45: error[invalid-type-guard-definition] Narrowed type `list[int]` is not assignable to the declared parameter type `list[object]`
 """
diff --git a/conformance/results/zuban/narrowing_typeis.toml b/conformance/results/zuban/narrowing_typeis.toml
index e62ce812..8e3c790b 100644
--- a/conformance/results/zuban/narrowing_typeis.toml
+++ b/conformance/results/zuban/narrowing_typeis.toml
@@ -2,13 +2,13 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-narrowing_typeis.py:105: error: "TypeIs" functions must have a positional argument  [misc]
 narrowing_typeis.py:110: error: "TypeIs" functions must have a positional argument  [misc]
-narrowing_typeis.py:132: error: Argument 1 to "takes_callable_str" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], str]"  [arg-type]
-narrowing_typeis.py:152: error: Argument 1 to "takes_callable_str_proto" has incompatible type "Callable[[object], TypeIs[int]]"; expected "CallableStrProto"  [arg-type]
-narrowing_typeis.py:169: error: Argument 1 to "takes_typeguard" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], TypeGuard[int]]"  [arg-type]
-narrowing_typeis.py:170: error: Argument 1 to "takes_typeis" has incompatible type "Callable[[object], TypeGuard[int]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
-narrowing_typeis.py:191: error: Argument 1 to "takes_int_typeis" has incompatible type "Callable[[object], TypeIs[bool]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
-narrowing_typeis.py:195: error: Narrowed type "str" is not a subtype of input type "int"  [narrowed-type-not-subtype]
-narrowing_typeis.py:199: error: Narrowed type "list[int]" is not a subtype of input type "list[object]"  [narrowed-type-not-subtype]
+narrowing_typeis.py:115: error: "TypeIs" functions must have a positional argument  [misc]
+narrowing_typeis.py:137: error: Argument 1 to "takes_callable_str" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], str]"  [arg-type]
+narrowing_typeis.py:157: error: Argument 1 to "takes_callable_str_proto" has incompatible type "Callable[[object], TypeIs[int]]"; expected "CallableStrProto"  [arg-type]
+narrowing_typeis.py:174: error: Argument 1 to "takes_typeguard" has incompatible type "Callable[[object], TypeIs[int]]"; expected "Callable[[object], TypeGuard[int]]"  [arg-type]
+narrowing_typeis.py:175: error: Argument 1 to "takes_typeis" has incompatible type "Callable[[object], TypeGuard[int]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
+narrowing_typeis.py:196: error: Argument 1 to "takes_int_typeis" has incompatible type "Callable[[object], TypeIs[bool]]"; expected "Callable[[object], TypeIs[int]]"  [arg-type]
+narrowing_typeis.py:200: error: Narrowed type "str" is not a subtype of input type "int"  [narrowed-type-not-subtype]
+narrowing_typeis.py:204: error: Narrowed type "list[int]" is not a subtype of input type "list[object]"  [narrowed-type-not-subtype]
 """
diff --git a/conformance/tests/narrowing_typeis.py b/conformance/tests/narrowing_typeis.py
index 8632e67a..d3bbb604 100644
--- a/conformance/tests/narrowing_typeis.py
+++ b/conformance/tests/narrowing_typeis.py
@@ -35,7 +35,12 @@ async def func2(val: int | Awaitable[int]):
         x: int = await val
         return x
     else:
-        assert_type(val, int)
+        # We can't say much here. The strictly correct answer is
+        # (int | Awaitable[int]) & ~Awaitable[Any], but conformant implementations
+        # may simplify this.
+        # But it should definitely remain assignable to `int | Awaitable[int]`.
+        y: int | Awaitable[int] = val
+        return y
 
 
 T_A = TypeVar("T_A", bound="A")