invalid default return value for AbstractDataProcessor methods

[davidnich]

    AbstractDataProviderType getExpectedType() {
        return getExpectedTypeImpl() ?? AbstractDataProviderType::anyType;
    }

    AbstractDataProviderType getReturnType() {
        return getReturnTypeImpl() ?? AbstractDataProviderType::anyType;
    }

leads to:

RUNTIME-TYPE-ERROR: <return statement> expects type 'object<AbstractDataProviderType>', but got an object of class 'Type' instead

Furthermore this error should be caught at parse time