SwiftUI Go-to-Definition in VSCode Fails: "Failed to load swiftinterface / No language service for generated-swift-interface/SwiftUI.swiftinterface"

[khanakia]

Issue Summary

When using VSCode with Swift and the SourceKit-LSP extension, attempting to use "Go to Definition" (or similar navigation features) on system framework types from SwiftUI (e.g. VStack, Image) fails with the following errors:

• "Failed to load swiftinterface /SwiftUI.swiftinterface"

Steps to Reproduce

1. Open a SwiftUI project in VSCode with SourceKit-LSP set up (using official Swift or Swift for VSCode extensions).
2. Cmd/Ctrl+Click or use "Go To Definition" on a symbol such as VStack or Image.
3. Observe: VSCode opens a read-only SwiftUI.swiftinterface tab, showing "Failed to load swiftinterface", and the Output panel displays errors similar to above.

Expected Behavior

Go To Definition should display the public interface (API surface and documentation comments) for system framework symbols like SwiftUI components, similar to how Xcode presents these interfaces.

Actual Behavior

• An error message: "Failed to load swiftinterface /SwiftUI.swiftinterface" is shown.
• No interface or documentation for system frameworks is visible.
• Repeated errors in the VSCode Output panel regarding lack of a language service for the generated swiftinterface file.

Vscode Output Logs for SourceKit Language Server

[Error - 09:45:09] Request textDocument/semanticTokens/full failed.
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 
[Error - 09:45:09] Request textDocument/inlayHint failed.
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 
[Error - 09:45:09] Request textDocument/semanticTokens/range failed.
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 
[Error - 09:45:09] Request textDocument/foldingRange failed.
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 
[Error - 09:45:09] Request textDocument/foldingRange failed.
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 
[Error - 09:45:18] Request textDocument/diagnostic failed.
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 
[Error - 09:45:18] Document pull failed for text document readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift
  Message: No language service for 'readonly://generated-swift-interface/SwiftUI.swiftinterface?moduleName%3DSwiftUI%26sourcekitdDocument%3DSwiftUI-995560FA-2332-4951-959B-BEF5714CB300%26buildSettingsFrom%3Dfile%3A%2F%2F%2FVolumes%2FD%2Fkhanakia%2FDownloads%2Fkeylistner%2Fkeylistner%2FContentView.swift' found
  Code: -32001 

Screen.Recording.2025-10-22.at.9.49.34.AM.mov

[ahoppen]

Thanks for the report, would you be able to enable extended logging, reproduce the issue and then attach the output of sourcekit-lsp diagnose?

Also, which version of the VS Code Swift Extension are you using? The readonly:// messages you posted make be suspect that you might still be on the deprecated extension https://marketplace.visualstudio.com/items?itemName=sswg.swift-lang instead of on https://marketplace.visualstudio.com/items?itemName=swiftlang.swift-vscode, which receives new updates.

[khanakia]

Yes, it was depreciated version installed. I just installed the latest one but still getting error now it's something else

Also attaching the diagnostic logs please check

sourcekit-lsp-diagnose-2025-10-22T11-49-34+05-30.zip

[ahoppen]

Interesting, I see a few oddities here but none of them should prevent the generated interface from being shown.

• The Unable to find folder for document warning should only prevent document symbols from being resolved in the document and I’m seeing that locally as well but I do get the generated interface’s contents. Filed Unable to find folder for document after jumping to a generated interface vscode-swift#1899 for this.
• Unexpectedly received reopen document notification for reference document in the log of the diagnose bundle: I’m not sure what exactly triggers the document re-open (usually it’s changed build settings but I don’t see any of that in the log). We’ll need to investigate but it ends up being a no-op after the fault is logged so this shouldn’t cause any issues. Probably triggered by updated build settings being sent by your push-based (legacy) BSP server

SourceKit-LSP receives the workspace/getReferenceDocument requests for the generated interface and we do return the contents of the SwiftUI interface from there, so everything looks good from that end.

Now a couple questions for you:

• Did you see the generated interface appear and then disappear again or something like that (this would point towards issues with the document reopen, though I don’t suspect this)
• You seem to be using a BSP server (legacy BSP protocol to be exact). If you create a new SwiftPM project, add import SwiftUI there, can you jump to the generated interface there?
• Which BSP server are you using?

[khanakia]

• Did you see the generated interface appear and then disappear again or something like that (this would point towards issues with the document reopen, though I don’t suspect this)
  Ans: NO

• You seem to be using a BSP server (legacy BSP protocol to be exact). If you create a new SwiftPM project, add import SwiftUI there, can you jump to the generated interface there?
  Ans: I created a project with SwiftPM then it works but when i create a porject using Xcode > MacOs App and then open in VsCode then it does not works

luci> swift -v

Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)

luci> xcodebuild -version
Xcode 26.0.1
Build version 17A400

[award999]

@khanakia could you run the Swift: Capture Diagnostic Bundle command so we can see the Swift extension log to see if the issue is there? My guess is that it's an editor issue, so could you run Developer: Open Logs Folder command as well and provide the main.log

[khanakia]

I just restarted everything and suddenly now it started working fine now even for the code created by xcode 🙌