support resolve generic types that doesn't specify any type arguments.

aioinject/context.py

@@ -115,9 +115,12 @@ async def resolve(
             for base in orig_bases:
                 if is_generic_alias(base):
                     args = base.__args__
-                    params = base.__origin__.__parameters__
-                    for param, arg in zip(params, args, strict=False):
-                        args_map[param.__name__] = arg
+                    if params := getattr(base.__origin__, "__parameters__", None):
+                        for param, arg in zip(params, args, strict=False):
+                            args_map[param.__name__] = arg
+            if not args_map:
+                # type may be generic though user didn't provide any type parameters
+                type_is_generic = False
 
 
         for dependency in provider.resolve_dependencies(

tests/features/test_generics.py

@@ -168,3 +168,21 @@ def __init__(self, service: TwoGeneric[T, str]) -> None:
         assert isinstance(instance.service.b, WithGenericDependency)
         assert instance.service.a.dependency == MEANING_OF_LIFE_INT
         assert instance.service.b.dependency == MEANING_OF_LIFE_STR
+
+
+
+async def test_can_resolve_generic_class_without_parameters() -> None:
+    class GenericClass(Generic[T]):
+        def __init__(self, a: int) -> None:
+            self.a = a
+
+        def so_generic(self) -> T:  # pragma: no cover
+            raise NotImplementedError
+
+    container = Container()
+    container.register(Scoped(GenericClass), Object(MEANING_OF_LIFE_INT))
+
+    async with container.context() as ctx:
+        instance = await ctx.resolve(GenericClass)
+        assert isinstance(instance, GenericClass)
+        assert instance.a == MEANING_OF_LIFE_INT