SourceKit-LSP is reporting wrong file for diagnostic related information

[adam-fowler]

Swift version

swift-driver version: 1.90.11.1 Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4)

Platform

macOS 14.5

Editor

VS Code

Does the issue reproduce with Swift 6?

Yes

Description

The related information attached to diagnostics reference the wrong file. It references the file the diagnostic occurred and not the file the related information is in.

Steps to Reproduce

1. In a VS Code project add file Test.swift with the following lines

   @available(*, unavailable)
   struct Test {}

2. In a second file Test2.swift reference type Test

   func test() {
   let t = Test()
   }

3. Notice diagnostic 'Test' is unavailable and then notice that the related information 'Test' has been explicitly marked unavailable here references a location in Test2.swift and not Test.swift

Logging

Here is the related response from the SourceKit-LSP output log

[Trace - 15:28:16] Received response 'textDocument/diagnostic - (423)' in 5ms.
Result: {
    "kind": "full",
    "items": [
        {
            "tags": [
                1
            ],
            "range": {
                "start": {
                    "line": 1,
                    "character": 8
                },
                "end": {
                    "line": 1,
                    "character": 8
                }
            },
            "codeActions": [
                {
                    "title": "Replace 'let t' with '_'",
                    "kind": "quickfix",
                    "edit": {
                        "changes": {
                            "file:///Users/adamfowler/Temp/RelatedInformation/Sources/RelatedInformation/Test2.swift": [
                                {
                                    "newText": "_",
                                    "range": {
                                        "end": {
                                            "character": 9,
                                            "line": 1
                                        },
                                        "start": {
                                            "line": 1,
                                            "character": 4
                                        }
                                    }
                                }
                            ]
                        }
                    }
                }
            ],
            "source": "sourcekitd",
            "message": "initialization of immutable value 't' was never used; consider replacing with assignment to '_' or removing it",
            "severity": 2
        },
        {
            "relatedInformation": [
                {
                    "location": {
                        "uri": "file:///Users/adamfowler/Temp/RelatedInformation/Sources/RelatedInformation/Test2.swift",
                        "range": {
                            "start": {
                                "line": 1,
                                "character": 7
                            },
                            "end": {
                                "character": 7,
                                "line": 1
                            }
                        }
                    },
                    "message": "'Test' has been explicitly marked unavailable here"
                }
            ],
            "source": "sourcekitd",
            "severity": 1,
            "range": {
                "start": {
                    "character": 12,
                    "line": 1
                },
                "end": {
                    "character": 16,
                    "line": 1
                }
            },
            "message": "'Test' is unavailable",
            "tags": []
        }
    ]
}

[ahoppen]

Synced to Apple’s issue tracker as rdar://130503535

[ahoppen]

Fixed in https://github.com/swiftlang/sourcekit-lsp/pull/1528