Factor None out of InstrumentType_co

Author: jenshnielsen

src/qcodes/parameters/array_parameter.py

@@ -133,9 +133,7 @@ def __init__(
         self,
         name: str,
         shape: Sequence[int],
-        # mypy seems to be confused here. The bound and default for InstrumentType_co
-        # contains None but mypy will now allow it as a default as of v 1.19.0
-        instrument: InstrumentType_co = None,  # type: ignore[assignment]
+        instrument: InstrumentType_co | None = None,
         label: str | None = None,
         unit: str | None = None,
         setpoints: Sequence[Any] | None = None,

src/qcodes/parameters/delegate_parameter.py

@@ -24,8 +24,8 @@
 _local_ParameterDataTypeVar = TypeVar("_local_ParameterDataTypeVar", default=Any)
 _local_InstrumentType_co = TypeVar(
     "_local_InstrumentType_co",
-    bound="InstrumentBase | None",
-    default="InstrumentBase | None",
+    bound="InstrumentBase",
+    default="InstrumentBase",
     covariant=True,
 )
 

src/qcodes/parameters/multi_parameter.py

@@ -141,9 +141,7 @@ def __init__(
         name: str,
         names: Sequence[str],
         shapes: Sequence[Sequence[int]],
-        # mypy seems to be confused here. The bound and default for InstrumentType_co
-        # contains None but mypy will now allow it as a default as of v 1.19.0
-        instrument: InstrumentType_co = None,  # type: ignore[assignment]
+        instrument: InstrumentType_co | None = None,
         labels: Sequence[str] | None = None,
         units: Sequence[str] | None = None,
         setpoints: Sequence[Sequence[Any]] | None = None,

src/qcodes/parameters/parameter.py

@@ -180,9 +180,7 @@ class Parameter(
     def __init__(
         self,
         name: str,
-        # mypy seems to be confused here. The bound and default for InstrumentType_co
-        # contains None but mypy will now allow it as a default as of v 1.19.0
-        instrument: InstrumentType_co = None,  # type: ignore[assignment]
+        instrument: InstrumentType_co | None = None,
         label: str | None = None,
         unit: str | None = None,
         get_cmd: str | Callable[..., Any] | Literal[False] | None = None,

src/qcodes/parameters/parameter_base.py

@@ -52,8 +52,8 @@
 # Type parameter "InstrumentType@ParameterBase" is invariant, but "None" is not the same as "InstrumentBase | None"
 InstrumentType_co = TypeVar(
     "InstrumentType_co",
-    bound="InstrumentBase | None",
-    default="InstrumentBase | None",
+    bound="InstrumentBase",
+    default="InstrumentBase",
     covariant=True,
 )
 
@@ -229,7 +229,7 @@ class ParameterBase(
     def __init__(
         self,
         name: str,
-        instrument: InstrumentType_co = None,  # type: ignore[assignment]
+        instrument: InstrumentType_co | None = None,
         snapshot_get: bool = True,
         metadata: Mapping[Any, Any] | None = None,
         step: float | None = None,
@@ -1063,7 +1063,7 @@ def register_name(self) -> str:
         return self._register_name or self.full_name
 
     @property
-    def instrument(self) -> InstrumentType_co:
+    def instrument(self) -> InstrumentType_co | None:
         """
         Return the first instrument that this parameter is bound to.
         E.g if this is bound to a channel it will return the channel