Improve descriptor error messages

alluka/_self_injecting.py

@@ -44,7 +44,7 @@
 
 
 class AsyncSelfInjecting(alluka.AsyncSelfInjecting[_CallbackSigT]):
-    """Class used to link a sync function to a client to make it self-injecting.
+    """Class used to link an async function to a client to make it self-injecting.
 
     Examples
     --------

alluka/_types.py

@@ -31,6 +31,8 @@
 """Internal types used by Alluka."""
 from __future__ import annotations
 
+from typing import Any
+
 __all__: list[str] = ["Injected", "InjectedDescriptor"]
 
 import enum
@@ -256,6 +258,11 @@ def __init__(
         self.callback = callback
         self.type = type
 
+    def __getattr__(self, __name: str) -> Any:
+        raise AttributeError(
+            "Tried accessing a parameter that was not injected yet. Did you forget to inject dependencies?"
+        )
+
 
 Injected = typing.Annotated[_T, InjectedTypes.TYPE]
 """Type alias used to declare a keyword argument as requiring an injected type.