Hmm, I think you misunderstood what inline function is.

In my simple word, inline function is a function that will be merged into the main caller function during compilation for supposing faster processing, at the cost of potential bigger executable size. Check the definition https://www.quora.com/What-is-an-inline-function-1

As for the your input, yes, if a function returns nullable item, we’ll still need to use ? within the let scope.