stubtest: fix edge case for bytes enum subclasses (python#15943)

Author: AlexWaygood

mypy/stubtest.py

@@ -1552,10 +1552,10 @@ def anytype() -> mypy.types.AnyType:
     fallback = mypy.types.Instance(type_info, [anytype() for _ in type_info.type_vars])
 
     value: bool | int | str
-    if isinstance(runtime, bytes):
-        value = bytes_to_human_readable_repr(runtime)
-    elif isinstance(runtime, enum.Enum) and isinstance(runtime.name, str):
+    if isinstance(runtime, enum.Enum) and isinstance(runtime.name, str):
         value = runtime.name
+    elif isinstance(runtime, bytes):
+        value = bytes_to_human_readable_repr(runtime)
     elif isinstance(runtime, (bool, int, str)):
         value = runtime
     else:

mypy/test/teststubtest.py

@@ -1068,6 +1068,26 @@ def spam(x=Flags4(0)): pass
             """,
             error="spam",
         )
+        yield Case(
+            stub="""
+            from typing_extensions import Final, Literal
+            class BytesEnum(bytes, enum.Enum):
+                a: bytes
+            FOO: Literal[BytesEnum.a]
+            BAR: Final = BytesEnum.a
+            BAZ: BytesEnum
+            EGGS: bytes
+            """,
+            runtime="""
+            class BytesEnum(bytes, enum.Enum):
+                a = b'foo'
+            FOO = BytesEnum.a
+            BAR = BytesEnum.a
+            BAZ = BytesEnum.a
+            EGGS = BytesEnum.a
+            """,
+            error=None,
+        )
 
     @collect_cases
     def test_decorator(self) -> Iterator[Case]: