diff --git a/conformance/results/mypy/directives_type_checking.toml b/conformance/results/mypy/directives_type_checking.toml
index 5e485e856..38420ca99 100644
--- a/conformance/results/mypy/directives_type_checking.toml
+++ b/conformance/results/mypy/directives_type_checking.toml
@@ -1,5 +1,6 @@
 conformant = "Pass"
 output = """
+directives_type_checking.py:14: error: List item 0 has incompatible type "str"; expected "int"  [list-item]
 """
 conformance_automated = "Pass"
 errors_diff = """
diff --git a/conformance/results/pyrefly/directives_type_checking.toml b/conformance/results/pyrefly/directives_type_checking.toml
index be211bd5b..0c9777d72 100644
--- a/conformance/results/pyrefly/directives_type_checking.toml
+++ b/conformance/results/pyrefly/directives_type_checking.toml
@@ -3,4 +3,5 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
+ERROR directives_type_checking.py:14:20-27: `list[str]` is not assignable to `list[int]` [bad-assignment]
 """
diff --git a/conformance/results/pyright/directives_type_checking.toml b/conformance/results/pyright/directives_type_checking.toml
index 5e485e856..d5ae85083 100644
--- a/conformance/results/pyright/directives_type_checking.toml
+++ b/conformance/results/pyright/directives_type_checking.toml
@@ -1,5 +1,7 @@
 conformant = "Pass"
 output = """
+directives_type_checking.py:14:21 - error: Type "list[str]" is not assignable to declared type "list[int]"
+  "Literal['foo']" is not assignable to "int" (reportAssignmentType)
 """
 conformance_automated = "Pass"
 errors_diff = """
diff --git a/conformance/results/ty/directives_type_checking.toml b/conformance/results/ty/directives_type_checking.toml
index cdd4d0cd9..7c82a4a01 100644
--- a/conformance/results/ty/directives_type_checking.toml
+++ b/conformance/results/ty/directives_type_checking.toml
@@ -2,4 +2,5 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
+directives_type_checking.py:14:20: error[invalid-assignment] Object of type `list[int | str]` is not assignable to `list[int]`
 """
diff --git a/conformance/results/zuban/directives_type_checking.toml b/conformance/results/zuban/directives_type_checking.toml
index cdd4d0cd9..cb24b659e 100644
--- a/conformance/results/zuban/directives_type_checking.toml
+++ b/conformance/results/zuban/directives_type_checking.toml
@@ -2,4 +2,5 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
+directives_type_checking.py:14: error: List item 0 has incompatible type "str"; expected "int"  [list-item]
 """
diff --git a/conformance/tests/directives_type_checking.py b/conformance/tests/directives_type_checking.py
index 55a2d52df..aaaaef52c 100644
--- a/conformance/tests/directives_type_checking.py
+++ b/conformance/tests/directives_type_checking.py
@@ -8,11 +8,20 @@
 
 
 if not TYPE_CHECKING:
-    a: int = "" # This should not generate an error
+    a: int = ""  # E? Many type checkers suppress all errors in `if not TYPE_CHECKING` blocks, though this is not currently specified
 
 if TYPE_CHECKING:
-    b: list[int] = [1, 2, 3]
+    x: list[int] = ["foo"]  # E: In a `if TYPE_CHECKING` block, type checkers should report all errors as normal
 else:
-    b: list[str] = ["a", "b", "c"]
+    x: list[str] = [42]  # E? Many type checkers suppress all errors in `else` blocks of `if TYPE_CHECKING`, though this is not currently specified
 
-assert_type(b, list[int])
+
+def foo(x: list[int], y: list[str]) -> None:
+    z: list[int] | list[str]
+
+    if TYPE_CHECKING:
+        z = x
+    else:
+        z = y
+
+    assert_type(z, list[int])