incorporate remaining comments

Author: makslevental

mlir/lib/Bindings/Python/IRCore.cpp

@@ -1913,6 +1913,8 @@ pybind11::object PyValue::maybeDownCast() {
  "mlirTypeID was expected to be non-null.");
  std::optional<pybind11::function> valueCaster =
  PyGlobals::get().lookupValueCaster(mlirTypeID, mlirTypeGetDialect(type));
+ // py::return_value_policy::move means use std::move to move the return value
+ // contents into a new instance that will be owned by Python.
  py::object thisObj = py::cast(this, py::return_value_policy::move);
  if (!valueCaster)
  return thisObj;

mlir/test/python/ir/value.py

@@ -366,7 +366,7 @@ def dont_cast_int_shouldnt_register(v):
  ...
 
  except RuntimeError as e:
- # CHECK: Value caster is already registered: <function testValueCasters.<locals>.cast_int at
+ # CHECK: Value caster is already registered: {{.*}}cast_int
  print(e)
 
  @register_value_caster(IntegerType.static_typeid, replace=True)