This statement is surprising to me. I haven't encountered any formal introduction of yield keyword in Swift. I believe it shouldn't be disregarded as a potential keyword, especially when it aligns well with the context.
As far as I remember, it was expected to be introduced through the modify accessor pitch, but it didn't proceed through the Swift evolution process. After researching other Swift evolution proposals, I found no mentions of yield. Additionally, it's not documented in The Swift Programming Language (TSPL) book.