reparent proper_plugin note

Author: wyattscarpenter

mypy/checker.py

@@ -7734,7 +7734,7 @@ def fail(
     ) -> ErrorInfo:
         """Produce an error message."""
         if isinstance(msg, ErrorMessage):
-            return self.msg.fail(msg.value, context, code=msg.code)
+            msg, code = msg.value, msg.code  # type: ignore[attr-defined] #TODO: https://github.com/python/mypy/issues/19891
         return self.msg.fail(msg, context, code=code)
 
     def note(
@@ -7744,12 +7744,12 @@ def note(
         offset: int = 0,
         *,
         code: ErrorCode | None = None,
+        parent_error: ErrorInfo | None = None,
     ) -> None:
         """Produce a note."""
         if isinstance(msg, ErrorMessage):
-            self.msg.note(msg.value, context, code=msg.code)
-            return
-        self.msg.note(msg, context, offset=offset, code=code)
+            msg, code = msg.value, msg.code  # type: ignore[attr-defined] #TODO: https://github.com/python/mypy/issues/19891
+        self.msg.note(msg, context, offset=offset, code=code, parent_error=parent_error)
 
     def iterable_item_type(
         self, it: Instance | CallableType | TypeType | Overloaded, context: Context

mypy/plugins/proper_plugin.py

@@ -63,7 +63,7 @@ def isinstance_proper_hook(ctx: FunctionContext) -> Type:
         ) and is_dangerous_target(right):
             if is_special_target(right):
                 return ctx.default_return_type
-            ctx.api.fail(
+            parent_error = ctx.api.fail(
                 "Never apply isinstance() to unexpanded types;"
                 " use mypy.types.get_proper_type() first",
                 ctx.context,
@@ -72,6 +72,7 @@ def isinstance_proper_hook(ctx: FunctionContext) -> Type:
                 "If you pass on the original type"
                 " after the check, always use its unexpanded version",
                 ctx.context,
+                parent_error=parent_error,
             )
     return ctx.default_return_type