Annotate the serializable decorators and fix the error type of Result

pyproject.toml

@@ -58,7 +58,7 @@ lint = [
     "ruff == 0.15.*",
 ]
 typecheck = [
-    "ty == 0.0.37", # Last version to not error on Returns Result
+    "ty >= 0.0.65",
 ]
 
 [tool.uv]

src/serialite/_decorators.py

@@ -3,7 +3,7 @@
 import dataclasses
 from dataclasses import MISSING
 from functools import wraps
-from typing import get_type_hints
+from typing import cast, get_type_hints
 
 from ._base import Serializable, Serializer
 from ._descriptors import classproperty
@@ -15,7 +15,7 @@
 
 
 # Inspired by https://stackoverflow.com/a/14412901/1485877
-def flexible_decorator(dec):
+def flexible_decorator[F](dec: F) -> F:
     """A decorator decorator to allow it to be used with or without parameters.
 
     Decorate a decorator like this:
@@ -59,7 +59,8 @@ def new_dec(*args, **kwargs):
             # Decorator called with arguments
             return lambda f: dec(f, *args, **kwargs)
 
-    return new_dec
+    # The wrapper accepts the same arguments as the bare decorator, so advertise its signature.
+    return cast(F, new_dec)
 
 
 def infer_fields_serializer(cls):
@@ -105,7 +106,7 @@ def infer_fields_serializer(cls):
 
 
 @flexible_decorator
-def serializable(cls):
+def serializable[T](cls: type[T]) -> type[T]:
     """Decorator that provides Serializable interface.
 
     This decorator can be applied to a dataclass. It inserts `SerializableMixin`
@@ -234,7 +235,7 @@ def infer_subclass_serializers(cls):
 
 
 @flexible_decorator
-def abstract_serializable(cls):
+def abstract_serializable[T](cls: type[T]) -> type[T]:
     """Decorator that provides AbstractSerializableMixin interface.
 
     This decorator can be applied to an abstract class. It inserts

src/serialite/_result.py

@@ -7,7 +7,6 @@
 from ._errors import Errors
 
 Success = result.Success
-Failure: type[result.Failure[Errors]] = result.Failure[Errors]
 Failure = result.Failure
 
-type Result[Output] = Success[Output] | Failure
+type Result[Output] = Success[Output] | Failure[Errors]