syntax highlighting broken

[cyrfer]

I have a .swift file with this code:

public struct MyWebView: UIViewRepresentable {

and I get the following error:

Cannot find type 'UIViewRepresentable' in scopeSourceKit

It seems like the correct toolchain is already selected, from the command palette:

I am not able to provide the exact path via the command palette, but I did provide the following folder "/bin" from this output

xcrun --find swift
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift

to the user and workspace settings:

I have been building my SDK package successfully via the CLI with:

# list available
xcodebuild -showdestinations -scheme MySDK

# select one of the results (name:iPhone 16 Pro)
TARGET_DESTINATION="9C34C3AD-D86D-464B-B8F6-7ACE24EF3025"

xcodebuild build \
  -scheme MySDK \
  -destination "id=$TARGET_DESTINATION" \
  -configuration Debug

[award999]

Can you run Swift: Capture Diagnostics Bundle and send the archive? If it cannot find the dependency, my guess is the project has not been built but let's check your setup

[cyrfer]

@award999 here you go. Thank you for checking.

vscode-diagnostics-2025-09-24T09-09-41-07-00.zip

[award999]

Nothing looks obviously out of place. It is using the macOS SDK by default, does your application target a different platform? Can you try to build your application and reload VSCode? Since 6.1, the LSP should build the dependencies it needs worth trying

[cyrfer]

Hi @award999 ,

does your application target a different platform?

That sounds suspicious. I am definitely targeting only iOS, not Mac.

Can you try to build your application and reload VSCode?

My initial post shows how I built previously. Are you referring to another way of building?

I appreciate your help!

[cyrfer]

@award999 I opened my swift package in Xcode, selected an iOS target, and built the package. Now syntax highlighting works in VSCode.

What happens in XCode that makes the VSCode Swift extension happy?

[award999]

So my guess is that the dependencies had not been built until you built them in Xcode. SourceKit-LSP needs the dependencies to be built to function correctly. By default the current platform's SDK will be used for building in VSCode and for setting up the LSP. Run the Swift: Select Target Platform... command and select the SDK (iOS in your case). You'll likely have to reload VSCode. As long as you're using Swift 6.1+ the the LSP should handle the automatic building of dependencies.

[award999]

@cyrfer let me know if setting things up that way seems to help

[cyrfer]

I have learned that sometimes I get syntax highlights for some things, not all, and sometimes I don't. Something changes and what was sort-of-working eventually stops. I am just living with it.

Maybe I'm using the wrong tool. I am new to iOS development and Swift, and I hoped I could develop in VSCode so I found this extension. My experience tells me it is not a great experience for iOS workflows, but maybe it is fine for macOS. At the moment I am jumping between VSCode, terminal, Copilot, and even Xcode once in a while.

[award999]

I don't think you're using the wrong tool. We do not simulate iOS for app development, but building and language support should work. If your project is built, then language support should work, and if not let's dig into it deeper. Having the project open in vscode, Xcode, and building from the terminal I could see some potential contention over the build folder. Now I did just notice something that I may have glanced over before, in the description you mention using xcodebuild to build your project, so you're not using SwiftPM? We do not support Xcode projects, just SwiftPM packages