SourceKit-LSP build failure

[hjyamauchi]

Description

I noticed in our downstream CI

C:\a\swift-build\swift-build\SourceCache\sourcekit-lsp\Sources\LanguageServerProtocolJSONRPC\JSONRPCConnection.swift:370:50: error: type '(RequestID) -> Optional<any ResponseType.Type>' does not conform to the 'Sendable' protocol
368 | 
369 |     // Setup callback for response type.
370 |     decoder.userInfo[.responseTypeCallbackKey] = { (id: RequestID) -> ResponseType.Type? in
    |                                                  |- error: type '(RequestID) -> Optional<any ResponseType.Type>' does not conform to the 'Sendable' protocol
    |                                                  `- note: a function type must be marked '@Sendable' to conform to 'Sendable'
371 |       guard let outstanding = self.outstandingRequests[id] else {
372 |         logger.error("Unknown request for \(id, privacy: .public)")

I guess it's due to the foundation change similar to #79333

Reproduction

Stack dump

No stack

Expected behavior

No build failure

Environment

Windows

Additional information

No response

[hjyamauchi]

CC @compnerd

[compnerd]

CC: @ahoppen

[ahoppen]

Should be fixed by swiftlang/sourcekit-lsp#1979