Difference between “optional chaining” and “optional call chaining” in Swift

Question

Swift中“可选链接”和“可选调用链接”之间在语义上有什么区别吗？

Answer 1

Provisionally I'll answer No, there is no semantic difference.

"Optional Chaining" is discussed extensively in "The Swift Programming Language (Swift 2 Prerelease), both in its own section (Optional Chaining) and in later discussions on protocols and types. I don't see "Optional Call Chaining" in that book.

Googling "optional call chaining" returns this question, so I'm not sure in what context "optional call chaining" occurs.