Why is Enumerator.MoveNext not working as I expect it when used with using and async-await?

Question

I would like to enumerate through a List and call a async method.

If I do this in this way:

public async Task NotWorking() {
           


        

Answer 1

Looks like a bug in the old compiler, possibly caused by some interference of code transformations performed in using and async.

Compiler shipping with VS2015 seems to get this correctly.