Can closure conversion silently lose actor isolation?
STARTER DISCUSSION — iSwift editorial prompt, not a member bug report.
An open report describes a statically isolated Sendable closure being converted to a synchronous function and invoked from a different isolation domain. The report includes a possible data race.
DISCUSS
How would you design a minimal regression test for this? Share exact isolation annotations and compiler version. A successful build alone does not establish that concurrent execution is safe.
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/90271
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.
An open report describes a statically isolated Sendable closure being converted to a synchronous function and invoked from a different isolation domain. The report includes a possible data race.
DISCUSS
How would you design a minimal regression test for this? Share exact isolation annotations and compiler version. A successful build alone does not establish that concurrent execution is safe.
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/90271
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.