Updates for Swift 6

Package.resolved

@@ -1,12 +1,13 @@
 {
+  "originHash" : "d1e34fdb2ca25d057f59ed9573c5bc295cbcdaed69e42def6d10243b96f90b79",
   "pins" : [
     {
       "identity" : "citron",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/dabrahams/citron.git",
       "state" : {
         "revision" : "d19a40c8de65b68fec0d224576d60565c1f7ccf1",
-        "version" : "2.1.5"
+        "version" : "2.1.7"
       }
     },
     {
@@ -28,5 +29,5 @@
       }
     }
   ],
-  "version" : 2
+  "version" : 3
 }

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.7
+// swift-tools-version: 6.0
 import PackageDescription
 import Foundation
 
@@ -26,7 +26,7 @@ let package = Package(
             targets: ["Lotsawa"]),
     ],
     dependencies: [
-      .package(url: "https://github.com/dabrahams/citron.git", from: "2.1.5"),
+      .package(url: "https://github.com/dabrahams/citron.git", from: "2.1.7"),
       .package(url: "https://github.com/SwiftPackageIndex/SPIManifest.git", from: "0.12.0")
     ]
       + docGenerationDependency,

Tests/LotsawaTests/Utils/DebugGrammarParser.citron

@@ -4,7 +4,7 @@
   import CitronParserModule
   import CitronLexerModule
 
-  extension _CitronParserUnexpectedTokenError : CustomDebugStringConvertible {
+  extension _CitronParserUnexpectedTokenError : @retroactive CustomDebugStringConvertible {
     public var debugDescription: String {
       if let t = token as? DebugGrammar.AST.Token {
         return "\n\(t.position): error: unexpected token (\(t), tokenCode: \(tokenCode))"

Tests/LotsawaTests/Utils/DebugGrammarScanner.swift

@@ -6,22 +6,23 @@ import CitronLexerModule
 let comment = #"(?://\P{Bidi_Class=B}*)"#
 
 /// A lexical analyzer for the grammar we use to describe other grammars for testing.
-let testGrammarScanner = Scanner<DebugGrammarParser.CitronTokenCode>(
-  literalStrings: [
-    "::=": .IS_DEFINED_AS,
-    "_": .UNDERSCORE,
-    "|": .ALTERNATION,
-  ],
-  patterns: [
-    /// A mapping from regular expression pattern to either a coresponding token ID,
-    /// or `nil` if the pattern is to be discarded (e.g. for whitespace).
-    #"[A-Za-z][-_A-Za-z0-9]*(?=\s*::=)"#: .LHS,
-    #"[A-Za-z][-_A-Za-z0-9]*(?!\s*::=)"#: .SYMBOL,
-    #"'([^\\']|\\.)*'"#: .LITERAL,
-    #"\s*"#: nil,
-    comment: nil,
-  ]
-)
+var testGrammarScanner : Scanner<DebugGrammarParser.CitronTokenCode> {
+  return .init(
+    literalStrings: [
+      "::=": .IS_DEFINED_AS,
+      "_": .UNDERSCORE,
+      "|": .ALTERNATION,
+    ],
+    patterns: [
+      /// A mapping from regular expression pattern to either a coresponding token ID,
+      /// or `nil` if the pattern is to be discarded (e.g. for whitespace).
+      #"[A-Za-z][-_A-Za-z0-9]*(?=\s*::=)"#: .LHS,
+      #"[A-Za-z][-_A-Za-z0-9]*(?!\s*::=)"#: .SYMBOL,
+      #"'([^\\']|\\.)*'"#: .LITERAL,
+      #"\s*"#: nil,
+      comment: nil,
+    ])
+}
 
 extension DebugGrammar.AST {