stubtest: include function name in overload assertion messages (#20063)

jorenham · web-flow · commit 94d0d7e3e57e · 2025-10-14T14:55:30.000-07:00
I just managed to cause this assertion to fail (I'll open an issue about
this soon), but the traceback did not tell me *where* in the stubs this
occurred. Knowing the full name of the relevant function would've made
the debugging process a lot easier.
diff --git a/mypy/stubtest.py b/mypy/stubtest.py
@@ -968,7 +968,7 @@ def from_overloadedfuncdef(stub: nodes.OverloadedFuncDef) -> Signature[nodes.Arg
 
         is_arg_pos_only: defaultdict[str, set[bool]] = defaultdict(set)
         for func in map(_resolve_funcitem_from_decorator, stub.items):
-            assert func is not None, "Failed to resolve decorated overload"
+            assert func is not None, f"Failed to resolve decorated overload of {stub.fullname!r}"
             args = maybe_strip_cls(stub.name, func.arguments)
             for index, arg in enumerate(args):
                 if (
@@ -984,7 +984,7 @@ def from_overloadedfuncdef(stub: nodes.OverloadedFuncDef) -> Signature[nodes.Arg
 
         all_args: dict[str, list[tuple[nodes.Argument, int]]] = {}
         for func in map(_resolve_funcitem_from_decorator, stub.items):
-            assert func is not None, "Failed to resolve decorated overload"
+            assert func is not None, f"Failed to resolve decorated overload of {stub.fullname!r}"
             args = maybe_strip_cls(stub.name, func.arguments)
             for index, arg in enumerate(args):
                 # For positional-only args, we allow overloads to have different names for the same
