> given that FFI is usually in a thin layer of application code that can sort out safety itself.
Apple is aiming far higher. They want [1] the ability to seamlessly replace C++ code anywhere with Swift code, to write subclasses of C++ classes in Swift, etc. without giving up performance.
[1] they likely won’t get there for all C++ code, but if they get to “with a few manual annotations” without giving up efficiency, that would be a major accomplishment.
Apple is aiming far higher. They want [1] the ability to seamlessly replace C++ code anywhere with Swift code, to write subclasses of C++ classes in Swift, etc. without giving up performance.
See https://github.com/swiftlang/swift-evolution/blob/main/visio...
and the video linked to in https://forums.swift.org/t/video-swift-as-c-successor-in-fou..., which shows how far they were a year ago.
[1] they likely won’t get there for all C++ code, but if they get to “with a few manual annotations” without giving up efficiency, that would be a major accomplishment.