Support for Returning Multiple Values in OutputExpression

I want to include multiple local parameters in the output of a rule. Here's a simplified version:
"Actions": {
"OnSuccess": {
"Name": "OutputExpression",
"Context": {
"Expression": "new { TempValueA = TempValueA, TempValueB = TempValueB, FinalResult = TempValueB / input.TotalUnits }"
}
}
}

But I get this error:
Exception while executing OutputExpressionAction: Expression is missing an 'as' clause
When I try to return in the above way.
How can I return multiple values from OutputExpression? Is there a supported way to include local params in the output?

Start at OutputExpressionAction, where the reported exception originates, and trace the expression-evaluation path for the required as clause. No source file or test is named; done would mean an agreed behavior for multiple returned values and local parameters, with coverage for the shown expression.