Library evolution: has an optional frozen value returned unexpected data?
STARTER DISCUSSION — iSwift editorial prompt, not a member bug report.
A Swift 6.4 report describes optional small frozen structs returning unexpected zero-filled values through dynamic dispatch when library evolution is enabled.
DISCUSS
If you maintain a binary framework, how do you test optional return values across class overrides and protocol witnesses? Compare a reduced case with and without library evolution; do not treat a layout change as a verified fix.
Include: Swift/Xcode version, operating system, build flags, expected result and actual result. Do not include passwords or private project code.
SOURCE
https://github.com/swiftlang/swift/issues/92338
The upstream report was open when checked on October 4, 2026. Status can change; read the issue before relying on any workaround. iSwift has not independently reproduced this bug.
A Swift 6.4 report describes optional small frozen structs returning unexpected zero-filled values through dynamic dispatch when library evolution is enabled.
DISCUSS
If you maintain a binary framework, how do you test optional return values across class overrides and protocol witnesses? Compare a reduced case with and without library evolution; do not treat a layout change as a verified fix.
Include: Swift/Xcode version, operating system, build flags, expected result and actual result. Do not include passwords or private project code.
SOURCE
https://github.com/swiftlang/swift/issues/92338
The upstream report was open when checked on October 4, 2026. Status can change; read the issue before relying on any workaround. iSwift has not independently reproduced this bug.