Make swift-syntax build in Swift 6 language mode

Author: ahoppen

Package.swift

@@ -294,7 +294,8 @@ let package = Package(
       dependencies: ["_InstructionCounter", "_SwiftSyntaxTestSupport", "SwiftIDEUtils", "SwiftParser", "SwiftSyntax"],
       exclude: ["Inputs"]
     ),
-  ]
+  ],
+  swiftLanguageVersions: [.v5, .version("6")]
 )
 
 // This is a fake target that depends on all targets in the package.

Sources/SwiftParser/ExpressionInterpretedAsVersionTuple.swift

@@ -10,7 +10,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if swift(>=6)
+@_spi(RawSyntax) public import SwiftSyntax
+#else
 @_spi(RawSyntax) import SwiftSyntax
+#endif
 
 extension ExprSyntax {
   /// Parse the source code of this node as a `VersionTupleSyntax`.

Sources/SwiftParser/TokenSpecSet.swift

@@ -10,11 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if swift(>=6)
-@_spi(RawSyntax) @_spi(ExperimentalLanguageFeatures) public import SwiftSyntax
-#else
 @_spi(RawSyntax) @_spi(ExperimentalLanguageFeatures) import SwiftSyntax
-#endif
 
 /// A set of `TokenSpecs`. We expect to consume one of the sets specs in the
 /// parser.

Sources/SwiftSyntaxMacrosTestSupport/Assertions.swift

@@ -63,7 +63,7 @@ public struct NoteSpec {
     message: String,
     line: Int,
     column: Int,
-    originatorFile: StaticString = #file,
+    originatorFile: StaticString = #filePath,
     originatorLine: UInt = #line
   ) {
     self.message = message

SwiftSyntaxDevUtils/Sources/swift-syntax-dev-utils/common/Paths.swift

@@ -14,7 +14,7 @@ import Foundation
 
 enum Paths {
   static var packageDir: URL {
-    URL(fileURLWithPath: #file)
+    URL(fileURLWithPath: #filePath)
       .deletingLastPathComponent()
       .deletingLastPathComponent()
       .deletingLastPathComponent()

Tests/PerformanceTest/InstructionsCountAssertion.swift

@@ -17,7 +17,7 @@ fileprivate var baselineURL: URL {
   if let baselineFile = ProcessInfo.processInfo.environment["BASELINE_FILE"] {
     return URL(fileURLWithPath: baselineFile)
   } else {
-    return URL(fileURLWithPath: #file)
+    return URL(fileURLWithPath: #filePath)
       .deletingLastPathComponent()
       .appendingPathComponent("baselines.json")
   }

Tests/PerformanceTest/ParsingPerformanceTests.swift

@@ -18,7 +18,7 @@ import _SwiftSyntaxTestSupport
 class ParsingPerformanceTests: XCTestCase {
 
   var inputFile: URL {
-    return URL(fileURLWithPath: #file)
+    return URL(fileURLWithPath: #filePath)
       .deletingLastPathComponent()
       .appendingPathComponent("Inputs")
       .appendingPathComponent("MinimalCollections.swift.input")

Tests/PerformanceTest/SyntaxClassifierPerformanceTests.swift

@@ -19,7 +19,7 @@ import _SwiftSyntaxTestSupport
 class SyntaxClassifierPerformanceTests: XCTestCase {
 
   var inputFile: URL {
-    return URL(fileURLWithPath: #file)
+    return URL(fileURLWithPath: #filePath)
       .deletingLastPathComponent()
       .appendingPathComponent("Inputs")
       .appendingPathComponent("MinimalCollections.swift.input")

Tests/PerformanceTest/VisitorPerformanceTests.swift

@@ -18,7 +18,7 @@ import _SwiftSyntaxTestSupport
 class VisitorPerformanceTests: XCTestCase {
 
   var inputFile: URL {
-    return URL(fileURLWithPath: #file)
+    return URL(fileURLWithPath: #filePath)
       .deletingLastPathComponent()
       .appendingPathComponent("Inputs")
       .appendingPathComponent("MinimalCollections.swift.input")

Tests/SwiftParserTest/ParserTests.swift

@@ -85,7 +85,7 @@ class ParserTests: ParserTestCase {
     }
   }
 
-  let packageDir = URL(fileURLWithPath: #file)
+  let packageDir = URL(fileURLWithPath: #filePath)
     .deletingLastPathComponent()
     .deletingLastPathComponent()
     .deletingLastPathComponent()

Tests/SwiftParserTest/SequentialToConcurrentEditTranslationTests.swift

@@ -37,7 +37,7 @@ func verifySequentialToConcurrentTranslation(
   _ sequential: [IncrementalEdit],
   _ expectedConcurrent: [IncrementalEdit],
   testString: String = longString,
-  file: StaticString = #file,
+  file: StaticString = #filePath,
   line: UInt = #line
 ) {
   let concurrent = ConcurrentEdits(fromSequential: sequential)

Tests/SwiftSyntaxMacroExpansionTest/LexicalContextTests.swift

@@ -200,8 +200,8 @@ struct AllLexicalContextsMacro: DeclarationMacro {
   }
 }
 
-public struct LexicalContextDescriptionMacro: ExpressionMacro {
-  public static func expansion(
+struct LexicalContextDescriptionMacro: ExpressionMacro {
+  static func expansion(
     of node: some FreestandingMacroExpansionSyntax,
     in context: some MacroExpansionContext
   ) throws -> ExprSyntax {