From 71ad4bd08597a316f7b6264d7ce6d7e3583a7582 Mon Sep 17 00:00:00 2001
From: "Jens H. Nielsen" <Jens.Nielsen@microsoft.com>
Date: Fri, 7 Feb 2025 13:31:13 +0100
Subject: [PATCH] Fix type checking with mypy

---
 src/qcodes/instrument/channel.py | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/qcodes/instrument/channel.py b/src/qcodes/instrument/channel.py
index 0b2e21503c6..9e47adf7b90 100644
--- a/src/qcodes/instrument/channel.py
+++ b/src/qcodes/instrument/channel.py
@@ -153,10 +153,10 @@ def __init__(
         self._parent = parent
         self._name = name
         if not isinstance(chan_type, type) or not issubclass(
-            chan_type, InstrumentChannel
+            chan_type, InstrumentModule
         ):
             raise ValueError(
-                "ChannelTuple can only hold instances of type InstrumentChannel"
+                "ChannelTuple can only hold instances of type InstrumentModule"
             )
         if not isinstance(multichan_paramclass, type) or not issubclass(
             multichan_paramclass, MultiChannelInstrumentParameter
@@ -166,7 +166,7 @@ def __init__(
                 "MultiChannelInstrumentParameter"
             )
 
-        self._chan_type = chan_type
+        self._chan_type: type[InstrumentModuleType] = chan_type
         self._snapshotable = snapshotable
         self._paramclass = multichan_paramclass
 
@@ -270,7 +270,9 @@ def __add__(self: Self, other: ChannelTuple) -> Self:
         if self._parent != other._parent:
             raise ValueError("Can only add channels from the same parent together.")
 
-        return type(self)(
+        # mypy does not understand that type[self] is type[self]
+        # it infers that type(self) == ChannelTuple[Any] e.g. not generic
+        return type(self)(  # type: ignore[return-value]
             self._parent,
             self._name,
             self._chan_type,
@@ -1066,7 +1068,7 @@ def exists_on_instrument(self) -> bool:
         return self._exists_on_instrument
 
 
-class AutoLoadableChannelList(ChannelList):
+class AutoLoadableChannelList(ChannelList[AutoLoadableInstrumentChannel]):
     """
     Extends the QCoDeS :class:`ChannelList` class to add the following features:
     - Automatically create channel objects on initialization
@@ -1112,7 +1114,7 @@ def __init__(
         self,
         parent: Instrument,
         name: str,
-        chan_type: type,
+        chan_type: type[AutoLoadableInstrumentChannel],
         chan_list: Sequence[AutoLoadableInstrumentChannel] | None = None,
         snapshotable: bool = True,
         multichan_paramclass: type = MultiChannelInstrumentParameter,
@@ -1121,7 +1123,7 @@ def __init__(
         super().__init__(
             parent, name, chan_type, chan_list, snapshotable, multichan_paramclass
         )
-        new_channels = self._chan_type.load_from_instrument(  # type: ignore[attr-defined]
+        new_channels = self._chan_type.load_from_instrument(
             self._parent, channel_list=self, **kwargs
         )
 
@@ -1139,7 +1141,7 @@ def add(self, **kwargs: Any) -> AutoLoadableInstrumentChannel:
             Newly created instance of the channel class
 
         """
-        new_channel = self._chan_type.new_instance(  # type: ignore[attr-defined]
+        new_channel = self._chan_type.new_instance(
             self._parent, create_on_instrument=True, channel_list=self, **kwargs
         )