[Syntax] Fix TriviaPiece.isNewline

In Swift, only 'CR', 'LF', and 'CR+LF' are considered newline
characters. `TriviaPiece.isNewline` should not return true for 'VT' and
'FF'.

Instead of using 'Swift.Character.isNewline', introduce 'TriviaTraits' in
CodeGeneration, and manually set them for each trivia piece kind.

Author: rintaro

CodeGeneration/Sources/SyntaxSupport/Trivia.swift

@@ -12,6 +12,19 @@
 
 import SwiftSyntax
 
+public struct TriviaTraits: OptionSet {
+  public var rawValue: UInt8
+
+  public init(rawValue: UInt8) {
+    self.rawValue = rawValue
+  }
+
+  public static var whitespace: Self { .init(rawValue: 1 << 0) }
+  public static var newline: Self { .init(rawValue: 1 << 1) }
+  public static var spaceOrTab: Self { .init(rawValue: 1 << 2) }
+  public static var comment: Self { .init(rawValue: 1 << 3) }
+}
+
 public class Trivia {
   /// The name of the trivia.
   public let name: TokenSyntax
@@ -32,7 +45,7 @@ public class Trivia {
   /// Indicates if the trivia represents a comment.
   ///
   /// If `true`, the trivia is some form of a comment in the Swift code.
-  public let isComment: Bool
+  public let traits: TriviaTraits
 
   /// The name of the trivia in lowercase.
   public var lowerName: TokenSyntax { .identifier(lowercaseFirstWord(name: name.text)) }
@@ -60,16 +73,6 @@ public class Trivia {
   /// If `true`, the trivia is made up of multiple characters.
   public var isCollection: Bool { charactersLen > 0 }
 
-  /// Indicates if the trivia contains only whitespace characters.
-  public var isBlank: Bool {
-    characters.contains { $0.isWhitespace }
-  }
-
-  /// Indicates if the trivia contains newline characters.
-  public var isNewLine: Bool {
-    characters.contains { $0.isNewline }
-  }
-
   /// Initializes a new `Trivia` instance.
   ///
   /// - Parameters:
@@ -83,12 +86,12 @@ public class Trivia {
     comment: SwiftSyntax.Trivia,
     characters: [Character] = [],
     swiftCharacters: [Character] = [],
-    isComment: Bool = false
+    traits: TriviaTraits = []
   ) {
     self.name = name
     self.comment = comment
-    self.isComment = isComment
     self.characters = characters
+    self.traits = traits
 
     // Swift sometimes doesn't support escaped characters like \f or \v;
     // we should allow specifying alternatives explicitly.
@@ -115,7 +118,7 @@ public let TRIVIAS: [Trivia] = [
   Trivia(
     name: "BlockComment",
     comment: #"A developer block comment, starting with '/*' and ending with '*/'."#,
-    isComment: true
+    traits: [.comment]
   ),
 
   Trivia(
@@ -126,7 +129,8 @@ public let TRIVIAS: [Trivia] = [
     ],
     swiftCharacters: [
       Character("\r")
-    ]
+    ],
+    traits: [.whitespace, .newline]
   ),
 
   Trivia(
@@ -139,19 +143,20 @@ public let TRIVIAS: [Trivia] = [
     swiftCharacters: [
       Character("\r"),
       Character("\n"),
-    ]
+    ],
+    traits: [.whitespace, .newline]
   ),
 
   Trivia(
     name: "DocBlockComment",
     comment: #"A documentation block comment, starting with '/**' and ending with '*/'."#,
-    isComment: true
+    traits: [.comment]
   ),
 
   Trivia(
     name: "DocLineComment",
     comment: #"A documentation line comment, starting with '///' and excluding the trailing newline."#,
-    isComment: true
+    traits: [.comment]
   ),
 
   // Swift don't support form feed '\f' so we use the raw unicode
@@ -163,13 +168,14 @@ public let TRIVIAS: [Trivia] = [
     ],
     swiftCharacters: [
       Character("\u{240C}")
-    ]
+    ],
+    traits: [.whitespace]
   ),
 
   Trivia(
     name: "LineComment",
     comment: #"A developer line comment, starting with '//' and excluding the trailing newline."#,
-    isComment: true
+    traits: [.comment]
   ),
 
   Trivia(
@@ -180,7 +186,8 @@ public let TRIVIAS: [Trivia] = [
     ],
     swiftCharacters: [
       Character("\n")
-    ]
+    ],
+    traits: [.whitespace, .newline]
   ),
 
   Trivia(
@@ -202,7 +209,8 @@ public let TRIVIAS: [Trivia] = [
     ],
     swiftCharacters: [
       Character(" ")
-    ]
+    ],
+    traits: [.whitespace, .spaceOrTab]
   ),
 
   Trivia(
@@ -213,7 +221,8 @@ public let TRIVIAS: [Trivia] = [
     ],
     swiftCharacters: [
       Character("\t")
-    ]
+    ],
+    traits: [.whitespace, .spaceOrTab]
   ),
 
   Trivia(
@@ -230,6 +239,7 @@ public let TRIVIAS: [Trivia] = [
     ],
     swiftCharacters: [
       Character("\u{2B7F}")
-    ]
+    ],
+    traits: [.whitespace]
   ),
 ]

CodeGeneration/Sources/generate-swift-syntax/templates/swiftsyntax/TriviaPiecesFile.swift

@@ -271,58 +271,52 @@ let triviaPiecesFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
 }
 
 fileprivate func generateIsHelpers(for pieceName: TokenSyntax) throws -> ExtensionDeclSyntax {
-  return try ExtensionDeclSyntax("extension \(pieceName)") {
-    DeclSyntax(
-      """
-      /// Returns `true` if this piece is a newline, space or tab.
-      public var isWhitespace: Bool {
-        return isSpaceOrTab || isNewline
-      }
-      """
-    )
-
-    try VariableDeclSyntax("public var isNewline: Bool") {
+  func generateHelper(_ header: SyntaxNodeString, trait: TriviaTraits) throws -> VariableDeclSyntax {
+    try VariableDeclSyntax(header) {
       try SwitchExprSyntax("switch self") {
-        for trivia in TRIVIAS {
-          if trivia.isNewLine {
-            SwitchCaseSyntax("case .\(trivia.enumCaseName):") {
-              StmtSyntax("return true")
-            }
+        for trivia in TRIVIAS where trivia.traits.contains(trait) {
+          SwitchCaseSyntax("case .\(trivia.enumCaseName):") {
+            StmtSyntax("return true")
           }
         }
         SwitchCaseSyntax("default:") {
           StmtSyntax("return false")
         }
       }
     }
+  }
+
+  return try ExtensionDeclSyntax("extension \(pieceName)") {
+    try generateHelper(
+      """
+      /// Returns `true` if this piece is a whitespace.
+      public var isWhitespace: Bool
+      """,
+      trait: .whitespace
+    )
 
-    DeclSyntax(
+    try generateHelper(
       """
-      public var isSpaceOrTab: Bool {
-        switch self {
-        case .spaces:
-          return true
-        case .tabs:
-          return true
-        default:
-          return false
-        }
-      }
+      /// Returns `true` if this piece is a newline, space or tab.
+      public var isNewline: Bool
+      """,
+      trait: .newline
+    )
+
+    try generateHelper(
       """
+      /// Returns `true` if this piece is a space or tab.
+      public var isSpaceOrTab: Bool
+      """,
+      trait: .spaceOrTab
     )
 
-    DeclSyntax(
+    try generateHelper(
       """
       /// Returns `true` if this piece is a comment.
-      public var isComment: Bool {
-        switch self {
-        case .lineComment, .blockComment, .docLineComment, .docBlockComment:
-          return true
-        default:
-          return false
-        }
-      }
-      """
+      public var isComment: Bool
+      """,
+      trait: .comment
     )
   }
 }

Sources/SwiftSyntax/generated/TriviaPieces.swift

@@ -443,12 +443,8 @@ extension RawTriviaPiece {
 }
 
 extension TriviaPiece {
-  /// Returns `true` if this piece is a newline, space or tab.
+  /// Returns `true` if this piece is a whitespace.
   public var isWhitespace: Bool {
-    return isSpaceOrTab || isNewline
-  }
-
-  public var isNewline: Bool {
     switch self {
     case .carriageReturns:
       return true
@@ -458,13 +454,32 @@ extension TriviaPiece {
       return true
     case .newlines:
       return true
+    case .spaces:
+      return true
+    case .tabs:
+      return true
     case .verticalTabs:
       return true
     default:
       return false
     }
   }
 
+  /// Returns `true` if this piece is a newline, space or tab.
+  public var isNewline: Bool {
+    switch self {
+    case .carriageReturns:
+      return true
+    case .carriageReturnLineFeeds:
+      return true
+    case .newlines:
+      return true
+    default:
+      return false
+    }
+  }
+
+  /// Returns `true` if this piece is a space or tab.
   public var isSpaceOrTab: Bool {
     switch self {
     case .spaces:
@@ -479,7 +494,13 @@ extension TriviaPiece {
   /// Returns `true` if this piece is a comment.
   public var isComment: Bool {
     switch self {
-    case .lineComment, .blockComment, .docLineComment, .docBlockComment:
+    case .blockComment:
+      return true
+    case .docBlockComment:
+      return true
+    case .docLineComment:
+      return true
+    case .lineComment:
       return true
     default:
       return false
@@ -488,12 +509,8 @@ extension TriviaPiece {
 }
 
 extension RawTriviaPiece {
-  /// Returns `true` if this piece is a newline, space or tab.
+  /// Returns `true` if this piece is a whitespace.
   public var isWhitespace: Bool {
-    return isSpaceOrTab || isNewline
-  }
-
-  public var isNewline: Bool {
     switch self {
     case .carriageReturns:
       return true
@@ -503,13 +520,32 @@ extension RawTriviaPiece {
       return true
     case .newlines:
       return true
+    case .spaces:
+      return true
+    case .tabs:
+      return true
     case .verticalTabs:
       return true
     default:
       return false
     }
   }
 
+  /// Returns `true` if this piece is a newline, space or tab.
+  public var isNewline: Bool {
+    switch self {
+    case .carriageReturns:
+      return true
+    case .carriageReturnLineFeeds:
+      return true
+    case .newlines:
+      return true
+    default:
+      return false
+    }
+  }
+
+  /// Returns `true` if this piece is a space or tab.
   public var isSpaceOrTab: Bool {
     switch self {
     case .spaces:
@@ -524,7 +560,13 @@ extension RawTriviaPiece {
   /// Returns `true` if this piece is a comment.
   public var isComment: Bool {
     switch self {
-    case .lineComment, .blockComment, .docLineComment, .docBlockComment:
+    case .blockComment:
+      return true
+    case .docBlockComment:
+      return true
+    case .docLineComment:
+      return true
+    case .lineComment:
       return true
     default:
       return false