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Build Information

Successful build of swift-chess-neo, reference 2.0.0 (36df37), with Swift 6.4 for Android on 23 Sep 2026 00:53:59 UTC.

Swift 6 data race errors: 0

Build Command

bash -c docker run --pull=always --rm -v "checkouts-53886769-0":/host -w "$PWD" -e JAVA_HOME="/root/.sdkman/candidates/java/current" -e SPI_BUILD="1" -e SPI_PROCESSING="1" registry.gitlab.com/saguaro1/spi-images:android-6.4-latest swift build --swift-sdk aarch64-unknown-linux-android28 2>&1

Build Log

 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
180 |
181 |   /// Black castling rights.
182 |   public static let black = CastlingRights(Right.black)
    |                     |- warning: static property 'black' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'black' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
183 |
184 |   /// Kingside castling rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:185:21: warning: static property 'kingside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
183 |
184 |   /// Kingside castling rights.
185 |   public static let kingside = CastlingRights(Right.kingside)
    |                     |- warning: static property 'kingside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'kingside' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
186 |
187 |   /// Queenside castling rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:188:21: warning: static property 'queenside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
186 |
187 |   /// Queenside castling rights.
188 |   public static let queenside = CastlingRights(Right.queenside)
    |                     |- warning: static property 'queenside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'queenside' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
189 |
190 |   /// The rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:31:23: warning: static property '_white' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
   :
29 |
30 |   /// White color regardless of Swift version.
31 |   internal static let _white = Color.white
   |                       |- warning: static property '_white' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_white' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
32 |
33 |   /// Black color regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:34:23: warning: static property '_black' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
   :
32 |
33 |   /// Black color regardless of Swift version.
34 |   internal static let _black = Color.black
   |                       |- warning: static property '_black' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_black' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
35 |
36 |   /// An array of all colors.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:37:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Color]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
   :
35 |
36 |   /// An array of all colors.
37 |   public static let all: [Color] = [.white, .black]
   |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Color]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
   |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
38 |
39 |   /// Whether the color is white or not.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:62:23: warning: static property '_a' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 60 |
 61 |   /// A regardless of Swift version.
 62 |   internal static let _a = File.a
    |                       |- warning: static property '_a' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_a' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 63 |
 64 |   /// B regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:65:23: warning: static property '_b' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 63 |
 64 |   /// B regardless of Swift version.
 65 |   internal static let _b = File.b
    |                       |- warning: static property '_b' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_b' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 66 |
 67 |   /// C regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:68:23: warning: static property '_c' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 66 |
 67 |   /// C regardless of Swift version.
 68 |   internal static let _c = File.c
    |                       |- warning: static property '_c' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_c' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 69 |
 70 |   /// D regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:71:23: warning: static property '_d' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 69 |
 70 |   /// D regardless of Swift version.
 71 |   internal static let _d = File.d
    |                       |- warning: static property '_d' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_d' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 72 |
 73 |   /// E regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:74:23: warning: static property '_e' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 72 |
 73 |   /// E regardless of Swift version.
 74 |   internal static let _e = File.e
    |                       |- warning: static property '_e' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_e' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 75 |
 76 |   /// F regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:77:23: warning: static property '_f' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 75 |
 76 |   /// F regardless of Swift version.
 77 |   internal static let _f = File.f
    |                       |- warning: static property '_f' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_f' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 78 |
 79 |   /// G regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:80:23: warning: static property '_g' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 78 |
 79 |   /// G regardless of Swift version.
 80 |   internal static let _g = File.g
    |                       |- warning: static property '_g' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_g' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 81 |
 82 |   /// H regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:83:23: warning: static property '_h' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 81 |
 82 |   /// H regardless of Swift version.
 83 |   internal static let _h = File.h
    |                       |- warning: static property '_h' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_h' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 84 |
 85 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:90:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[File]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 88 |
 89 |   /// An array of all files.
 90 |   public static let all: [File] = [.a, .b, .c, .d, .e, .f, .g, .h]
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[File]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 91 |
 92 |   /// The column index of `self`.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:35:25: warning: static property '_draw' is not concurrency-safe because non-'Sendable' type 'Game.Outcome' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 24 |
 25 |   /// A chess game outcome.
 26 |   public enum Outcome: Hashable, CustomStringConvertible {
    |               `- note: consider making enum 'Outcome' conform to the 'Sendable' protocol
 27 |
 28 |     /// A win for a `Color`.
    :
 33 |
 34 |     /// Draw.
 35 |     internal static let _draw = Outcome.draw
    |                         |- warning: static property '_draw' is not concurrency-safe because non-'Sendable' type 'Game.Outcome' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_draw' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 36 |
 37 |     /// Win.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:240:10: warning: associated value 'wrongKingCount' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Color'
238 |
239 |     /// Found number other than 1 for king count.
240 |     case wrongKingCount(Color)
    |          `- warning: associated value 'wrongKingCount' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Color'
241 |
242 |     /// King missing for castling right.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:22:13: note: consider making enum 'Color' conform to the 'Sendable' protocol
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:243:10: warning: associated value 'missingKing' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
241 |
242 |     /// King missing for castling right.
243 |     case missingKing(CastlingRights.Right)
    |          `- warning: associated value 'missingKing' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
244 |
245 |     /// Rook missing for castling right.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:27:15: note: consider making enum 'Right' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:246:10: warning: associated value 'missingRook' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
244 |
245 |     /// Rook missing for castling right.
246 |     case missingRook(CastlingRights.Right)
    |          `- warning: associated value 'missingRook' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
247 |
248 |     /// Wrong rank for en passant target.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:27:15: note: consider making enum 'Right' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:249:10: warning: associated value 'wrongEnPassantTargetRank' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Rank'
247 |
248 |     /// Wrong rank for en passant target.
249 |     case wrongEnPassantTargetRank(Rank)
    |          `- warning: associated value 'wrongEnPassantTargetRank' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Rank'
250 |
251 |     /// Non empty en passant target square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Rank.swift:24:13: note: consider making enum 'Rank' conform to the 'Sendable' protocol
 22 | ///
 23 | /// `Rank`s refer to the eight rows of a chess board, beginning with 1 at the bottom and ending with 8 at the top.
 24 | public enum Rank: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'Rank' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in rank.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:252:10: warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
250 |
251 |     /// Non empty en passant target square.
252 |     case nonEmptyEnPassantTarget(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
253 |
254 |     /// Pawn missing for previous en passant.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:252:10: warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
250 |
251 |     /// Non empty en passant target square.
252 |     case nonEmptyEnPassantTarget(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
253 |
254 |     /// Pawn missing for previous en passant.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:22:15: note: consider making struct 'Piece' conform to the 'Sendable' protocol
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:255:10: warning: associated value 'missingEnPassantPawn' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Square'
253 |
254 |     /// Pawn missing for previous en passant.
255 |     case missingEnPassantPawn(Square)
    |          `- warning: associated value 'missingEnPassantPawn' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Square'
256 |
257 |     /// Piece found at start of en passant move.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:258:10: warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
256 |
257 |     /// Piece found at start of en passant move.
258 |     case nonEmptyEnPassantSquare(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
259 |
260 |   }
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:258:10: warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
256 |
257 |     /// Piece found at start of en passant move.
258 |     case nonEmptyEnPassantSquare(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
259 |
260 |   }
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:22:15: note: consider making struct 'Piece' conform to the 'Sendable' protocol
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:268:10: warning: associated value 'missingPiece' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Square'
266 |
267 |     /// Missing piece at a square.
268 |     case missingPiece(Square)
    |          `- warning: associated value 'missingPiece' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Square'
269 |
270 |     /// Attempted illegal move.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:271:10: warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Move'
269 |
270 |     /// Attempted illegal move.
271 |     case illegalMove(Move, Color, Board)
    |          `- warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Move'
272 |
273 |     /// Could not promote with a piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Move.swift:22:15: note: consider making struct 'Move' conform to the 'Sendable' protocol
 20 |
 21 | /// A chess move from a start `Square` to an end `Square`.
 22 | public struct Move: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Move' conform to the 'Sendable' protocol
 23 |
 24 |   /// The move's start square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:271:10: warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Color'
269 |
270 |     /// Attempted illegal move.
271 |     case illegalMove(Move, Color, Board)
    |          `- warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Color'
272 |
273 |     /// Could not promote with a piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:22:13: note: consider making enum 'Color' conform to the 'Sendable' protocol
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:271:10: warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Board'
269 |
270 |     /// Attempted illegal move.
271 |     case illegalMove(Move, Color, Board)
    |          `- warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Board'
272 |
273 |     /// Could not promote with a piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Board.swift:24:15: note: consider making struct 'Board' conform to the 'Sendable' protocol
 22 | ///
 23 | /// Pieces map to separate instances of `Bitboard` which can be retrieved with `bitboard(for:)`.
 24 | public struct Board: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Board' conform to the 'Sendable' protocol
 25 |
 26 |   /// A chess board space.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:274:10: warning: associated value 'invalidPromotion' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Piece.Kind'
272 |
273 |     /// Could not promote with a piece kind.
274 |     case invalidPromotion(Piece.Kind)
    |          `- warning: associated value 'invalidPromotion' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Piece.Kind'
275 |
276 |     /// The error message.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:25:15: note: consider making enum 'Kind' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:46:25: warning: static property '_pawn' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 44 |
 45 |     /// Pawn
 46 |     internal static let _pawn = Kind.pawn
    |                         |- warning: static property '_pawn' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_pawn' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 47 |
 48 |     /// Knight
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:49:25: warning: static property '_knight' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 47 |
 48 |     /// Knight
 49 |     internal static let _knight = Kind.knight
    |                         |- warning: static property '_knight' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_knight' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 50 |
 51 |     /// Bishop
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:52:25: warning: static property '_bishop' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 50 |
 51 |     /// Bishop
 52 |     internal static let _bishop = Kind.bishop
    |                         |- warning: static property '_bishop' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_bishop' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 53 |
 54 |     /// Rook
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:55:25: warning: static property '_rook' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 53 |
 54 |     /// Rook
 55 |     internal static let _rook = Kind.rook
    |                         |- warning: static property '_rook' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_rook' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 56 |
 57 |     /// Queen
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:58:25: warning: static property '_queen' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 56 |
 57 |     /// Queen
 58 |     internal static let _queen = Kind.queen
    |                         |- warning: static property '_queen' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_queen' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 59 |
 60 |     /// King
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:61:25: warning: static property '_king' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 59 |
 60 |     /// King
 61 |     internal static let _king = Kind.king
    |                         |- warning: static property '_king' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_king' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 62 |
 63 |     /// An array of all piece kinds.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:64:23: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece.Kind]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 62 |
 63 |     /// An array of all piece kinds.
 64 |     public static let all: [Kind] = [.pawn, .knight, .bishop, .rook, .queen, .king]
    |                       |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece.Kind]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 65 |
 66 |     /// The piece kind's name.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:140:23: warning: static property '_whiteNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
138 |   }
139 |
140 |   internal static let _whiteNonQueens: [Piece] = whitePieces.filter({ !$0.kind.isQueen })
    |                       |- warning: static property '_whiteNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_whiteNonQueens' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
141 |
142 |   internal static let _blackNonQueens: [Piece] = blackPieces.filter({ !$0.kind.isQueen })
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:142:23: warning: static property '_blackNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
140 |   internal static let _whiteNonQueens: [Piece] = whitePieces.filter({ !$0.kind.isQueen })
141 |
142 |   internal static let _blackNonQueens: [Piece] = blackPieces.filter({ !$0.kind.isQueen })
    |                       |- warning: static property '_blackNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_blackNonQueens' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
143 |
144 |   internal static func _nonQueens(for color: Color) -> [Piece] {
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:149:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
147 |
148 |   /// An array of all pieces.
149 |   public static let all: [Piece] = {
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
150 |     return [.white, .black].reduce([]) { pieces, color in
151 |       return pieces + Kind.all.map({ Piece(kind: $0, color: color) })
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:156:21: warning: static property 'whitePieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
154 |
155 |   /// An array of all white pieces.
156 |   public static let whitePieces: [Piece] = all.filter({ $0.color.isWhite })
    |                     |- warning: static property 'whitePieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'whitePieces' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
157 |
158 |   /// An array of all black pieces.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:159:21: warning: static property 'blackPieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
157 |
158 |   /// An array of all black pieces.
159 |   public static let blackPieces: [Piece] = all.filter({ $0.color.isBlack })
    |                     |- warning: static property 'blackPieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'blackPieces' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
160 |
161 |   /// Returns an array of all pieces for `color`.
/host/spi-builder-workspace/Sources/SwiftChessCore/Rank.swift:66:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Rank]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// `Rank`s refer to the eight rows of a chess board, beginning with 1 at the bottom and ending with 8 at the top.
 24 | public enum Rank: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'Rank' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in rank.
    :
 64 |
 65 |   /// An array of all ranks.
 66 |   public static let all: [Rank] = [1, 2, 3, 4, 5, 6, 7, 8]
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Rank]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 67 |
 68 |   /// The row index of `self`.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:226:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Square]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
    :
224 |
225 |   /// An array of all squares.
226 |   public static let all: [Square] = (0..<64).compactMap(Square.init(rawValue:))
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Square]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
227 |
228 |   /// The file of `self`.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:31:14: warning: let '_whitePawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 29 |
 30 | /// A lookup table of all white pawn attack bitboards.
 31 | internal let _whitePawnAttackTable = Square.all.map { square in
    |              |- warning: let '_whitePawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_whitePawnAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 32 |   return Bitboard(square: square)._pawnAttacks(for: ._white)
 33 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:36:14: warning: let '_blackPawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 34 |
 35 | /// A lookup table of all black pawn attack bitboards.
 36 | internal let _blackPawnAttackTable = Square.all.map { square in
    |              |- warning: let '_blackPawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_blackPawnAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 37 |   return Bitboard(square: square)._pawnAttacks(for: ._black)
 38 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:41:14: warning: let '_kingAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 39 |
 40 | /// A lookup table of all king attack bitboards.
 41 | internal let _kingAttackTable = Square.all.map { square in
    |              |- warning: let '_kingAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_kingAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 42 |   return Bitboard(square: square)._kingAttacks()
 43 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:46:14: warning: let '_knightAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 44 |
 45 | /// A lookup table of all knight attack bitboards.
 46 | internal let _knightAttackTable = Square.all.map { square in
    |              |- warning: let '_knightAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_knightAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 47 |   return Bitboard(square: square)._knightAttacks()
 48 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:85:14: warning: let '_betweenTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 | /// A lookup table of squares between two squares.
 85 | internal let _betweenTable: [Bitboard] = {
    |              |- warning: let '_betweenTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_betweenTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 86 |   var table = [Bitboard](repeating: 0, count: 2080)
 87 |   for start in Square.all {
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:97:14: warning: let '_lineTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 95 |
 96 | /// A lookup table of lines for two squares.
 97 | internal let _lineTable: [Bitboard] = {
    |              |- warning: let '_lineTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_lineTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 98 |   var table = [Bitboard](repeating: 0, count: 2080)
 99 |   for start in Square.all {
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Variant.swift:31:23: warning: static property '_standard' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess variant that defines how a `Board` is populated or how a `Game` is played.
22 | public enum Variant {
   |             `- note: consider making enum 'Variant' conform to the 'Sendable' protocol
23 |
24 |   /// Standard chess.
   :
29 |
30 |   /// Standard regardless of Swift version.
31 |   internal static let _standard = Variant.standard
   |                       |- warning: static property '_standard' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_standard' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
32 |
33 |   /// UpsideDown regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Variant.swift:34:23: warning: static property '_upsideDown' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess variant that defines how a `Board` is populated or how a `Game` is played.
22 | public enum Variant {
   |             `- note: consider making enum 'Variant' conform to the 'Sendable' protocol
23 |
24 |   /// Standard chess.
   :
32 |
33 |   /// UpsideDown regardless of Swift version.
34 |   internal static let _upsideDown = Variant.upsideDown
   |                       |- warning: static property '_upsideDown' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_upsideDown' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
35 |
36 |   /// `self` is standard variant.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:226:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Square]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
    :
224 |
225 |   /// An array of all squares.
226 |   public static let all: [Square] = (0..<64).compactMap(Square.init(rawValue:))
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Square]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
227 |
228 |   /// The file of `self`.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
[45 / 55] SwiftChessCore
/host/spi-builder-workspace/Sources/SwiftChessCore/Rank.swift:66:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Rank]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// `Rank`s refer to the eight rows of a chess board, beginning with 1 at the bottom and ending with 8 at the top.
 24 | public enum Rank: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'Rank' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in rank.
    :
 64 |
 65 |   /// An array of all ranks.
 66 |   public static let all: [Rank] = [1, 2, 3, 4, 5, 6, 7, 8]
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Rank]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 67 |
 68 |   /// The row index of `self`.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:31:14: warning: let '_whitePawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 29 |
 30 | /// A lookup table of all white pawn attack bitboards.
 31 | internal let _whitePawnAttackTable = Square.all.map { square in
    |              |- warning: let '_whitePawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_whitePawnAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 32 |   return Bitboard(square: square)._pawnAttacks(for: ._white)
 33 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:36:14: warning: let '_blackPawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 34 |
 35 | /// A lookup table of all black pawn attack bitboards.
 36 | internal let _blackPawnAttackTable = Square.all.map { square in
    |              |- warning: let '_blackPawnAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_blackPawnAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 37 |   return Bitboard(square: square)._pawnAttacks(for: ._black)
 38 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:41:14: warning: let '_kingAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 39 |
 40 | /// A lookup table of all king attack bitboards.
 41 | internal let _kingAttackTable = Square.all.map { square in
    |              |- warning: let '_kingAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_kingAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 42 |   return Bitboard(square: square)._kingAttacks()
 43 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:46:14: warning: let '_knightAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 44 |
 45 | /// A lookup table of all knight attack bitboards.
 46 | internal let _knightAttackTable = Square.all.map { square in
    |              |- warning: let '_knightAttackTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_knightAttackTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 47 |   return Bitboard(square: square)._knightAttacks()
 48 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:85:14: warning: let '_betweenTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 | /// A lookup table of squares between two squares.
 85 | internal let _betweenTable: [Bitboard] = {
    |              |- warning: let '_betweenTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_betweenTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 86 |   var table = [Bitboard](repeating: 0, count: 2080)
 87 |   for start in Square.all {
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Tables.swift:97:14: warning: let '_lineTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 95 |
 96 | /// A lookup table of lines for two squares.
 97 | internal let _lineTable: [Bitboard] = {
    |              |- warning: let '_lineTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |              |- note: add '@MainActor' to make let '_lineTable' part of global actor 'MainActor'
    |              `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 98 |   var table = [Bitboard](repeating: 0, count: 2080)
 99 |   for start in Square.all {
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:82:15: note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Variant.swift:31:23: warning: static property '_standard' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess variant that defines how a `Board` is populated or how a `Game` is played.
22 | public enum Variant {
   |             `- note: consider making enum 'Variant' conform to the 'Sendable' protocol
23 |
24 |   /// Standard chess.
   :
29 |
30 |   /// Standard regardless of Swift version.
31 |   internal static let _standard = Variant.standard
   |                       |- warning: static property '_standard' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_standard' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
32 |
33 |   /// UpsideDown regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Variant.swift:34:23: warning: static property '_upsideDown' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess variant that defines how a `Board` is populated or how a `Game` is played.
22 | public enum Variant {
   |             `- note: consider making enum 'Variant' conform to the 'Sendable' protocol
23 |
24 |   /// Standard chess.
   :
32 |
33 |   /// UpsideDown regardless of Swift version.
34 |   internal static let _upsideDown = Variant.upsideDown
   |                       |- warning: static property '_upsideDown' is not concurrency-safe because non-'Sendable' type 'Variant' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_upsideDown' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
35 |
36 |   /// `self` is standard variant.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
[50 / 55] SwiftChessCore
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:46:13: warning: let '_bitboardTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 44 |
 45 | /// A lookup table of bitboards for all squares.
 46 | private let _bitboardTable: [Bitboard] = (0..<64).map { Bitboard(rawValue: 1 << $0) }
    |             |- warning: let '_bitboardTable' is not concurrency-safe because non-'Sendable' type '[Bitboard]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |             |- note: add '@MainActor' to make let '_bitboardTable' part of global actor 'MainActor'
    |             `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 47 |
 48 | /// The De Bruijn multiplier.
    :
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:60:13: warning: let '_notFileA' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 58 |
 59 | /// Mask for bits not in File A.
 60 | private let _notFileA: Bitboard = 0xfefe_fefe_fefe_fefe
    |             |- warning: let '_notFileA' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |             |- note: add '@MainActor' to make let '_notFileA' part of global actor 'MainActor'
    |             `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 61 |
 62 | /// Mask for bits not in Files A and B.
    :
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:63:13: warning: let '_notFileAB' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 61 |
 62 | /// Mask for bits not in Files A and B.
 63 | private let _notFileAB: Bitboard = 0xfcfc_fcfc_fcfc_fcfc
    |             |- warning: let '_notFileAB' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |             |- note: add '@MainActor' to make let '_notFileAB' part of global actor 'MainActor'
    |             `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 64 |
 65 | /// Mask for bits not in File H.
    :
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:66:13: warning: let '_notFileH' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 64 |
 65 | /// Mask for bits not in File H.
 66 | private let _notFileH: Bitboard = 0x7f7f_7f7f_7f7f_7f7f
    |             |- warning: let '_notFileH' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |             |- note: add '@MainActor' to make let '_notFileH' part of global actor 'MainActor'
    |             `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 67 |
 68 | /// Mask for bits not in Files G and H.
    :
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:69:13: warning: let '_notFileGH' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 67 |
 68 | /// Mask for bits not in Files G and H.
 69 | private let _notFileGH: Bitboard = 0x3f3f_3f3f_3f3f_3f3f
    |             |- warning: let '_notFileGH' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |             |- note: add '@MainActor' to make let '_notFileGH' part of global actor 'MainActor'
    |             `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 70 |
 71 | /// A bitmap of sixty-four bits suitable for storing squares for various pieces.
    :
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:112:25: warning: static property '_north' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
110 |
111 |     /// North regardless of Swift version.
112 |     internal static let _north = ShiftDirection.north
    |                         |- warning: static property '_north' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_north' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
113 |
114 |     /// South regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:115:25: warning: static property '_south' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
113 |
114 |     /// South regardless of Swift version.
115 |     internal static let _south = ShiftDirection.south
    |                         |- warning: static property '_south' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_south' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
116 |
117 |     /// East regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:118:25: warning: static property '_east' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
116 |
117 |     /// East regardless of Swift version.
118 |     internal static let _east = ShiftDirection.east
    |                         |- warning: static property '_east' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_east' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
119 |
120 |     /// West regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:121:25: warning: static property '_west' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
119 |
120 |     /// West regardless of Swift version.
121 |     internal static let _west = ShiftDirection.west
    |                         |- warning: static property '_west' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_west' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
122 |
123 |     /// Northeast regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:124:25: warning: static property '_northeast' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
122 |
123 |     /// Northeast regardless of Swift version.
124 |     internal static let _northeast = ShiftDirection.northeast
    |                         |- warning: static property '_northeast' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_northeast' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
125 |
126 |     /// Southeast regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:127:25: warning: static property '_southeast' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
125 |
126 |     /// Southeast regardless of Swift version.
127 |     internal static let _southeast = ShiftDirection.southeast
    |                         |- warning: static property '_southeast' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_southeast' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
128 |
129 |     /// Northwest regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:130:25: warning: static property '_northwest' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
128 |
129 |     /// Northwest regardless of Swift version.
130 |     internal static let _northwest = ShiftDirection.northwest
    |                         |- warning: static property '_northwest' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_northwest' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
131 |
132 |     /// Southwest regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:133:25: warning: static property '_southwest' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 83 |
 84 |   /// A bitboard shift direction.
 85 |   public enum ShiftDirection {
    |               `- note: consider making enum 'ShiftDirection' conform to the 'Sendable' protocol
 86 |
 87 |     /// North direction.
    :
131 |
132 |     /// Southwest regardless of Swift version.
133 |     internal static let _southwest = ShiftDirection.southwest
    |                         |- warning: static property '_southwest' is not concurrency-safe because non-'Sendable' type 'Bitboard.ShiftDirection' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_southwest' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
134 |
135 |   }
/host/spi-builder-workspace/Sources/SwiftChessCore/Bitboard.swift:156:21: warning: static property 'edges' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 80 | /// - see also: [Bitboard (Wikipedia)](https://en.wikipedia.org/wiki/Bitboard ),
 81 | ///            [Bitboards (Chess Programming Wiki)](https://chessprogramming.org/Bitboards)
 82 | public struct Bitboard: RawRepresentable, Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Bitboard' conform to the 'Sendable' protocol
 83 |
 84 |   /// A bitboard shift direction.
    :
154 |
155 |   /// The edges of a board.
156 |   public static let edges: Bitboard = 0xff81_8181_8181_81ff
    |                     |- warning: static property 'edges' is not concurrency-safe because non-'Sendable' type 'Bitboard' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'edges' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
157 |
158 |   /// The corresponding value of the "raw" type.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:42:23: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
    :
 40 |
 41 |     /// All rights.
 42 |     public static let all: [Right] = [
    |                       |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 43 |       .whiteKingside, .whiteQueenside, .blackKingside, .blackQueenside,
 44 |     ]
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:47:23: warning: static property 'white' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
    :
 45 |
 46 |     /// White rights.
 47 |     public static let white: [Right] = all.filter({ $0.color.isWhite })
    |                       |- warning: static property 'white' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'white' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 48 |
 49 |     /// Black rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:50:23: warning: static property 'black' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
    :
 48 |
 49 |     /// Black rights.
 50 |     public static let black: [Right] = all.filter({ $0.color.isBlack })
    |                       |- warning: static property 'black' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'black' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 51 |
 52 |     /// Kingside rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:53:23: warning: static property 'kingside' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
    :
 51 |
 52 |     /// Kingside rights.
 53 |     public static let kingside: [Right] = all.filter({ $0.side.isKingside })
    |                       |- warning: static property 'kingside' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'kingside' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 54 |
 55 |     /// Queenside rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:56:23: warning: static property 'queenside' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
    :
 54 |
 55 |     /// Queenside rights.
 56 |     public static let queenside: [Right] = all.filter({ $0.side.isQueenside })
    |                       |- warning: static property 'queenside' is not concurrency-safe because non-'Sendable' type '[CastlingRights.Right]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'queenside' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 57 |
 58 |     /// The color for `self`.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:176:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
174 |
175 |   /// All castling rights.
176 |   public static let all = CastlingRights(Right.all)
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
177 |
178 |   /// White castling rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:179:21: warning: static property 'white' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
177 |
178 |   /// White castling rights.
179 |   public static let white = CastlingRights(Right.white)
    |                     |- warning: static property 'white' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'white' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
180 |
181 |   /// Black castling rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:182:21: warning: static property 'black' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
180 |
181 |   /// Black castling rights.
182 |   public static let black = CastlingRights(Right.black)
    |                     |- warning: static property 'black' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'black' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
183 |
184 |   /// Kingside castling rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:185:21: warning: static property 'kingside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
183 |
184 |   /// Kingside castling rights.
185 |   public static let kingside = CastlingRights(Right.kingside)
    |                     |- warning: static property 'kingside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'kingside' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
186 |
187 |   /// Queenside castling rights.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:188:21: warning: static property 'queenside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Defines whether a `Color` has the right to castle for a `Board.Side`.
 24 | public struct CastlingRights: CustomStringConvertible {
    |               `- note: consider making struct 'CastlingRights' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
    :
186 |
187 |   /// Queenside castling rights.
188 |   public static let queenside = CastlingRights(Right.queenside)
    |                     |- warning: static property 'queenside' is not concurrency-safe because non-'Sendable' type 'CastlingRights' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'queenside' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
189 |
190 |   /// The rights.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:31:23: warning: static property '_white' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
   :
29 |
30 |   /// White color regardless of Swift version.
31 |   internal static let _white = Color.white
   |                       |- warning: static property '_white' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_white' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
32 |
33 |   /// Black color regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:34:23: warning: static property '_black' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
   :
32 |
33 |   /// Black color regardless of Swift version.
34 |   internal static let _black = Color.black
   |                       |- warning: static property '_black' is not concurrency-safe because non-'Sendable' type 'Color' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                       |- note: add '@MainActor' to make static property '_black' part of global actor 'MainActor'
   |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
35 |
36 |   /// An array of all colors.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:37:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Color]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
   :
35 |
36 |   /// An array of all colors.
37 |   public static let all: [Color] = [.white, .black]
   |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Color]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
   |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
   |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
38 |
39 |   /// Whether the color is white or not.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:62:23: warning: static property '_a' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 60 |
 61 |   /// A regardless of Swift version.
 62 |   internal static let _a = File.a
    |                       |- warning: static property '_a' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_a' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 63 |
 64 |   /// B regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:65:23: warning: static property '_b' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 63 |
 64 |   /// B regardless of Swift version.
 65 |   internal static let _b = File.b
    |                       |- warning: static property '_b' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_b' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 66 |
 67 |   /// C regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:68:23: warning: static property '_c' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 66 |
 67 |   /// C regardless of Swift version.
 68 |   internal static let _c = File.c
    |                       |- warning: static property '_c' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_c' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 69 |
 70 |   /// D regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:71:23: warning: static property '_d' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 69 |
 70 |   /// D regardless of Swift version.
 71 |   internal static let _d = File.d
    |                       |- warning: static property '_d' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_d' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 72 |
 73 |   /// E regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:74:23: warning: static property '_e' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 72 |
 73 |   /// E regardless of Swift version.
 74 |   internal static let _e = File.e
    |                       |- warning: static property '_e' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_e' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 75 |
 76 |   /// F regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:77:23: warning: static property '_f' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 75 |
 76 |   /// F regardless of Swift version.
 77 |   internal static let _f = File.f
    |                       |- warning: static property '_f' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_f' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 78 |
 79 |   /// G regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:80:23: warning: static property '_g' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 78 |
 79 |   /// G regardless of Swift version.
 80 |   internal static let _g = File.g
    |                       |- warning: static property '_g' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_g' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 81 |
 82 |   /// H regardless of Swift version.
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:83:23: warning: static property '_h' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 81 |
 82 |   /// H regardless of Swift version.
 83 |   internal static let _h = File.h
    |                       |- warning: static property '_h' is not concurrency-safe because non-'Sendable' type 'File' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_h' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 84 |
 85 | }
/host/spi-builder-workspace/Sources/SwiftChessCore/File.swift:90:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[File]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 22 | ///
 23 | /// Files refer to the eight columns of a chess board, beginning with A and ending with H from left to right.
 24 | public enum File: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'File' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in file.
    :
 88 |
 89 |   /// An array of all files.
 90 |   public static let all: [File] = [.a, .b, .c, .d, .e, .f, .g, .h]
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[File]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 91 |
 92 |   /// The column index of `self`.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:35:25: warning: static property '_draw' is not concurrency-safe because non-'Sendable' type 'Game.Outcome' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 24 |
 25 |   /// A chess game outcome.
 26 |   public enum Outcome: Hashable, CustomStringConvertible {
    |               `- note: consider making enum 'Outcome' conform to the 'Sendable' protocol
 27 |
 28 |     /// A win for a `Color`.
    :
 33 |
 34 |     /// Draw.
 35 |     internal static let _draw = Outcome.draw
    |                         |- warning: static property '_draw' is not concurrency-safe because non-'Sendable' type 'Game.Outcome' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_draw' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 36 |
 37 |     /// Win.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:240:10: warning: associated value 'wrongKingCount' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Color'
238 |
239 |     /// Found number other than 1 for king count.
240 |     case wrongKingCount(Color)
    |          `- warning: associated value 'wrongKingCount' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Color'
241 |
242 |     /// King missing for castling right.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:22:13: note: consider making enum 'Color' conform to the 'Sendable' protocol
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:243:10: warning: associated value 'missingKing' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
241 |
242 |     /// King missing for castling right.
243 |     case missingKing(CastlingRights.Right)
    |          `- warning: associated value 'missingKing' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
244 |
245 |     /// Rook missing for castling right.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:27:15: note: consider making enum 'Right' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:246:10: warning: associated value 'missingRook' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
244 |
245 |     /// Rook missing for castling right.
246 |     case missingRook(CastlingRights.Right)
    |          `- warning: associated value 'missingRook' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'CastlingRights.Right'
247 |
248 |     /// Wrong rank for en passant target.
/host/spi-builder-workspace/Sources/SwiftChessCore/CastlingRights.swift:27:15: note: consider making enum 'Right' conform to the 'Sendable' protocol
 25 |
 26 |   /// A castling right.
 27 |   public enum Right: String, CustomStringConvertible {
    |               `- note: consider making enum 'Right' conform to the 'Sendable' protocol
 28 |
 29 |     /// White can castle kingside.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:249:10: warning: associated value 'wrongEnPassantTargetRank' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Rank'
247 |
248 |     /// Wrong rank for en passant target.
249 |     case wrongEnPassantTargetRank(Rank)
    |          `- warning: associated value 'wrongEnPassantTargetRank' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Rank'
250 |
251 |     /// Non empty en passant target square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Rank.swift:24:13: note: consider making enum 'Rank' conform to the 'Sendable' protocol
 22 | ///
 23 | /// `Rank`s refer to the eight rows of a chess board, beginning with 1 at the bottom and ending with 8 at the top.
 24 | public enum Rank: Int, Comparable, CustomStringConvertible {
    |             `- note: consider making enum 'Rank' conform to the 'Sendable' protocol
 25 |
 26 |   /// A direction in rank.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:252:10: warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
250 |
251 |     /// Non empty en passant target square.
252 |     case nonEmptyEnPassantTarget(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
253 |
254 |     /// Pawn missing for previous en passant.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:252:10: warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
250 |
251 |     /// Non empty en passant target square.
252 |     case nonEmptyEnPassantTarget(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantTarget' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
253 |
254 |     /// Pawn missing for previous en passant.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:22:15: note: consider making struct 'Piece' conform to the 'Sendable' protocol
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:255:10: warning: associated value 'missingEnPassantPawn' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Square'
253 |
254 |     /// Pawn missing for previous en passant.
255 |     case missingEnPassantPawn(Square)
    |          `- warning: associated value 'missingEnPassantPawn' of 'Sendable'-conforming enum 'PositionError' has non-Sendable type 'Square'
256 |
257 |     /// Piece found at start of en passant move.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:258:10: warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
256 |
257 |     /// Piece found at start of en passant move.
258 |     case nonEmptyEnPassantSquare(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Square'
259 |
260 |   }
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:258:10: warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
256 |
257 |     /// Piece found at start of en passant move.
258 |     case nonEmptyEnPassantSquare(Square, Piece)
    |          `- warning: associated value 'nonEmptyEnPassantSquare' of 'Sendable'-conforming enum 'PositionError' contains non-Sendable type 'Piece'
259 |
260 |   }
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:22:15: note: consider making struct 'Piece' conform to the 'Sendable' protocol
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:268:10: warning: associated value 'missingPiece' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Square'
266 |
267 |     /// Missing piece at a square.
268 |     case missingPiece(Square)
    |          `- warning: associated value 'missingPiece' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Square'
269 |
270 |     /// Attempted illegal move.
/host/spi-builder-workspace/Sources/SwiftChessCore/Square.swift:27:13: note: consider making enum 'Square' conform to the 'Sendable' protocol
 25 | ///
 26 | /// A `Square` can be one of sixty-four possible values, ranging from `A1` to `H8`.
 27 | public enum Square: Int, CustomStringConvertible {
    |             `- note: consider making enum 'Square' conform to the 'Sendable' protocol
 28 |
 29 |   /// A1 square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:271:10: warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Move'
269 |
270 |     /// Attempted illegal move.
271 |     case illegalMove(Move, Color, Board)
    |          `- warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Move'
272 |
273 |     /// Could not promote with a piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Move.swift:22:15: note: consider making struct 'Move' conform to the 'Sendable' protocol
 20 |
 21 | /// A chess move from a start `Square` to an end `Square`.
 22 | public struct Move: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Move' conform to the 'Sendable' protocol
 23 |
 24 |   /// The move's start square.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:271:10: warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Color'
269 |
270 |     /// Attempted illegal move.
271 |     case illegalMove(Move, Color, Board)
    |          `- warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Color'
272 |
273 |     /// Could not promote with a piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Color.swift:22:13: note: consider making enum 'Color' conform to the 'Sendable' protocol
20 |
21 | /// A chess color.
22 | public enum Color: String, CustomStringConvertible {
   |             `- note: consider making enum 'Color' conform to the 'Sendable' protocol
23 |
24 |   /// White chess color.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:271:10: warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Board'
269 |
270 |     /// Attempted illegal move.
271 |     case illegalMove(Move, Color, Board)
    |          `- warning: associated value 'illegalMove' of 'Sendable'-conforming enum 'ExecutionError' contains non-Sendable type 'Board'
272 |
273 |     /// Could not promote with a piece kind.
/host/spi-builder-workspace/Sources/SwiftChessCore/Board.swift:24:15: note: consider making struct 'Board' conform to the 'Sendable' protocol
 22 | ///
 23 | /// Pieces map to separate instances of `Bitboard` which can be retrieved with `bitboard(for:)`.
 24 | public struct Board: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Board' conform to the 'Sendable' protocol
 25 |
 26 |   /// A chess board space.
/host/spi-builder-workspace/Sources/SwiftChessCore/Game.swift:274:10: warning: associated value 'invalidPromotion' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Piece.Kind'
272 |
273 |     /// Could not promote with a piece kind.
274 |     case invalidPromotion(Piece.Kind)
    |          `- warning: associated value 'invalidPromotion' of 'Sendable'-conforming enum 'ExecutionError' has non-Sendable type 'Piece.Kind'
275 |
276 |     /// The error message.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:25:15: note: consider making enum 'Kind' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:46:25: warning: static property '_pawn' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 44 |
 45 |     /// Pawn
 46 |     internal static let _pawn = Kind.pawn
    |                         |- warning: static property '_pawn' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_pawn' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 47 |
 48 |     /// Knight
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:49:25: warning: static property '_knight' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 47 |
 48 |     /// Knight
 49 |     internal static let _knight = Kind.knight
    |                         |- warning: static property '_knight' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_knight' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 50 |
 51 |     /// Bishop
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:52:25: warning: static property '_bishop' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 50 |
 51 |     /// Bishop
 52 |     internal static let _bishop = Kind.bishop
    |                         |- warning: static property '_bishop' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_bishop' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 53 |
 54 |     /// Rook
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:55:25: warning: static property '_rook' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 53 |
 54 |     /// Rook
 55 |     internal static let _rook = Kind.rook
    |                         |- warning: static property '_rook' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_rook' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 56 |
 57 |     /// Queen
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:58:25: warning: static property '_queen' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 56 |
 57 |     /// Queen
 58 |     internal static let _queen = Kind.queen
    |                         |- warning: static property '_queen' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_queen' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 59 |
 60 |     /// King
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:61:25: warning: static property '_king' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 59 |
 60 |     /// King
 61 |     internal static let _king = Kind.king
    |                         |- warning: static property '_king' is not concurrency-safe because non-'Sendable' type 'Piece.Kind' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                         |- note: add '@MainActor' to make static property '_king' part of global actor 'MainActor'
    |                         `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 62 |
 63 |     /// An array of all piece kinds.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:64:23: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece.Kind]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 23 |
 24 |   /// A piece kind.
 25 |   public enum Kind: Int {
    |               `- note: consider making enum 'Kind' conform to the 'Sendable' protocol
 26 |
 27 |     /// Pawn piece kind.
    :
 62 |
 63 |     /// An array of all piece kinds.
 64 |     public static let all: [Kind] = [.pawn, .knight, .bishop, .rook, .queen, .king]
    |                       |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece.Kind]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 65 |
 66 |     /// The piece kind's name.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:140:23: warning: static property '_whiteNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
138 |   }
139 |
140 |   internal static let _whiteNonQueens: [Piece] = whitePieces.filter({ !$0.kind.isQueen })
    |                       |- warning: static property '_whiteNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_whiteNonQueens' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
141 |
142 |   internal static let _blackNonQueens: [Piece] = blackPieces.filter({ !$0.kind.isQueen })
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:142:23: warning: static property '_blackNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
140 |   internal static let _whiteNonQueens: [Piece] = whitePieces.filter({ !$0.kind.isQueen })
141 |
142 |   internal static let _blackNonQueens: [Piece] = blackPieces.filter({ !$0.kind.isQueen })
    |                       |- warning: static property '_blackNonQueens' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                       |- note: add '@MainActor' to make static property '_blackNonQueens' part of global actor 'MainActor'
    |                       `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
143 |
144 |   internal static func _nonQueens(for color: Color) -> [Piece] {
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:149:21: warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
147 |
148 |   /// An array of all pieces.
149 |   public static let all: [Piece] = {
    |                     |- warning: static property 'all' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'all' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
150 |     return [.white, .black].reduce([]) { pieces, color in
151 |       return pieces + Kind.all.map({ Piece(kind: $0, color: color) })
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:156:21: warning: static property 'whitePieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
154 |
155 |   /// An array of all white pieces.
156 |   public static let whitePieces: [Piece] = all.filter({ $0.color.isWhite })
    |                     |- warning: static property 'whitePieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'whitePieces' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
157 |
158 |   /// An array of all black pieces.
/host/spi-builder-workspace/Sources/SwiftChessCore/Piece.swift:159:21: warning: static property 'blackPieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
 20 |
 21 | /// A chess piece.
 22 | public struct Piece: Hashable, CustomStringConvertible {
    |               `- note: consider making struct 'Piece' conform to the 'Sendable' protocol
 23 |
 24 |   /// A piece kind.
    :
157 |
158 |   /// An array of all black pieces.
159 |   public static let blackPieces: [Piece] = all.filter({ $0.color.isBlack })
    |                     |- warning: static property 'blackPieces' is not concurrency-safe because non-'Sendable' type '[Piece]' may have shared mutable state; this is an error in the Swift 6 language mode [#]8;;https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable\MutableGlobalVariable]8;;\]
    |                     |- note: add '@MainActor' to make static property 'blackPieces' part of global actor 'MainActor'
    |                     `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
160 |
161 |   /// Returns an array of all pieces for `color`.
[#MutableGlobalVariable]: <https://docs.swift.org/compiler/documentation/diagnostics/mutable-global-variable>
Build complete! (6.16 secs)
Build complete.
{
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  ],
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  "name" : "swift-chess-neo",
  "path" : "/host/spi-builder-workspace",
  "platforms" : [
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  "products" : [
    {
      "name" : "SwiftChessCore",
      "targets" : [
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      "type" : {
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        ]
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    },
    {
      "name" : "SwiftChessUI",
      "targets" : [
        "SwiftChessUI"
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      "type" : {
        "library" : [
          "automatic"
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      }
    }
  ],
  "targets" : [
    {
      "c99name" : "SwiftChessUI",
      "module_type" : "SwiftTarget",
      "name" : "SwiftChessUI",
      "path" : "Sources/SwiftChessUI",
      "product_memberships" : [
        "SwiftChessUI"
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      "sources" : [
        "Board+View.swift"
      ],
      "target_dependencies" : [
        "SwiftChessCore"
      ],
      "type" : "library"
    },
    {
      "c99name" : "SwiftChessCoreTests",
      "module_type" : "SwiftTarget",
      "name" : "SwiftChessCoreTests",
      "path" : "Tests/SwiftChessCoreTests",
      "sources" : [
        "MiscTests.swift",
        "PGNParsingTests.swift",
        "SwiftChessCoreTests.swift"
      ],
      "target_dependencies" : [
        "SwiftChessCore"
      ],
      "type" : "test"
    },
    {
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      "module_type" : "SwiftTarget",
      "name" : "SwiftChessCore",
      "path" : "Sources/SwiftChessCore",
      "product_memberships" : [
        "SwiftChessCore",
        "SwiftChessUI"
      ],
      "sources" : [
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        "Board.swift",
        "CastlingRights.swift",
        "Color.swift",
        "File.swift",
        "Game.swift",
        "InternalTypes.swift",
        "Minimax.swift",
        "Move.swift",
        "PGN.swift",
        "PGNMove.swift",
        "Piece.swift",
        "Player.swift",
        "Rank.swift",
        "Sequence+Sage.swift",
        "Square.swift",
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        "Variant.swift"
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      "type" : "library"
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}
android-6.4-latest: Pulling from saguaro1/spi-images
Digest: sha256:abadcff584c273feba50641b454858d377ba30b35ea7287a94f45ebd8afd0ea0
Status: Image is up to date for registry.gitlab.com/saguaro1/spi-images:android-6.4-latest
Done.