Model parameter modifiers as a ModifierList

This allows more flexibility in the future if more parameters get added in the future and if those might be ordered arbitrarily. It also makes fixing a parsing issue in the C++ parser easier.

Author: ahoppen

CodeGeneration/Sources/SyntaxSupport/gyb_generated/DeclNodes.swift

@@ -722,12 +722,10 @@ public let DECL_NODES: [Node] = [
                kind: "AttributeList",
                isOptional: true,
                collectionElementName: "Attribute"),
-         Child(name: "IsolatedToken",
-               kind: "Token",
-               isOptional: true),
-         Child(name: "ConstToken",
-               kind: "Token",
-               isOptional: true),
+         Child(name: "Modifiers",
+               kind: "ModifierList",
+               isOptional: true,
+               collectionElementName: "Modifier"),
          Child(name: "FirstName",
                kind: "Token",
                isOptional: true,

Package.swift

@@ -172,7 +172,7 @@ let package = Package(
     .testTarget(
       name: "SwiftParserTest",
       dependencies: ["SwiftDiagnostics", "SwiftOperators", "SwiftParser",
-                     "_SwiftSyntaxTestSupport"]
+                     "_SwiftSyntaxTestSupport", "SwiftSyntaxBuilder"]
     ),
     .testTarget(
       name: "SwiftOperatorsTest",

Sources/SwiftParser/Declarations.swift

@@ -1257,6 +1257,26 @@ extension Parser {
     }
   }
 
+  mutating func parseParameterModifiers(for subject: ParameterSubject) -> RawModifierListSyntax? {
+    var elements = [RawDeclModifierSyntax]()
+    var loopCondition = LoopProgressCondition()
+    MODIFIER_LOOP: while loopCondition.evaluate(currentToken) {
+      switch self.at(anyIn: ParameterModifier.self) {
+      case (._const, let handle)?:
+        elements.append(RawDeclModifierSyntax(name: self.eat(handle), detail: nil, arena: self.arena))
+      case (.isolated, let handle)? where !self.lookahead().startsParameterName(subject.isClosure):
+        elements.append(RawDeclModifierSyntax(name: self.eat(handle), detail: nil, arena: self.arena))
+      default:
+        break MODIFIER_LOOP
+      }
+    }
+    if elements.isEmpty {
+      return nil
+    } else {
+      return RawModifierListSyntax(elements: elements, arena: self.arena)
+    }
+  }
+
   @_spi(RawSyntax)
   public mutating func parseParameterClause(for subject: ParameterSubject) -> RawParameterClauseSyntax {
     let (unexpectedBeforeLParen, lparen) = self.expect(.leftParen)
@@ -1280,16 +1300,7 @@ extension Parser {
           attrs = self.parseAttributeList()
         }
 
-        let unexpectedBeforeIsolated: RawUnexpectedNodesSyntax?
-        let isolated: RawTokenSyntax?
-        if self.currentToken.isContextualKeyword("isolated") &&
-            !self.lookahead().startsParameterName(subject.isClosure) {
-          (unexpectedBeforeIsolated, isolated) = self.expectContextualKeyword("isolated")
-        } else {
-          unexpectedBeforeIsolated = nil
-          isolated = nil
-        }
-        let const = self.consumeIfContextualKeyword("_const")
+        let modifiers = parseParameterModifiers(for: subject)
 
         let firstName: RawTokenSyntax?
         let secondName: RawTokenSyntax?
@@ -1350,9 +1361,7 @@ extension Parser {
         keepGoing = trailingComma != nil
         elements.append(RawFunctionParameterSyntax(
           attributes: attrs,
-          unexpectedBeforeIsolated,
-          isolatedToken: isolated,
-          constToken: const,
+          modifiers: modifiers,
           firstName: firstName,
           secondName: secondName,
           unexpectedBeforeColon,

Sources/SwiftParser/RawTokenKindSubset.swift

@@ -631,6 +631,30 @@ enum MatchingPatternStart: RawTokenKindSubset {
   }
 }
 
+enum ParameterModifier: RawTokenKindSubset {
+  case _const
+  case isolated
+
+  init?(lexeme: Lexer.Lexeme) {
+    switch (lexeme.tokenKind, lexeme.tokenText) {
+    case (.identifier, "_const"): self = ._const
+    case (.identifier, "isolate"): self = .isolated
+    default: return nil
+    }
+  }
+
+  var rawTokenKind: RawTokenKind {
+    return .identifier
+  }
+
+  var contextualKeyword: SyntaxText? {
+    switch self {
+    case ._const: return "_const"
+    case .isolated: return "isolated"
+    }
+  }
+}
+
 enum PrimaryExpressionStart: RawTokenKindSubset {
   case __column__Keyword
   case __dso_handle__Keyword

Sources/SwiftSyntax/Raw/gyb_generated/RawSyntaxNodes.swift

@@ -7295,11 +7295,9 @@ public struct RawFunctionParameterSyntax: RawSyntaxNodeProtocol, RawSyntaxToSynt
   public init(
     _ unexpectedBeforeAttributes: RawUnexpectedNodesSyntax? = nil,
     attributes: RawAttributeListSyntax?,
-    _ unexpectedBetweenAttributesAndIsolatedToken: RawUnexpectedNodesSyntax? = nil,
-    isolatedToken: RawTokenSyntax?,
-    _ unexpectedBetweenIsolatedTokenAndConstToken: RawUnexpectedNodesSyntax? = nil,
-    constToken: RawTokenSyntax?,
-    _ unexpectedBetweenConstTokenAndFirstName: RawUnexpectedNodesSyntax? = nil,
+    _ unexpectedBetweenAttributesAndModifiers: RawUnexpectedNodesSyntax? = nil,
+    modifiers: RawModifierListSyntax?,
+    _ unexpectedBetweenModifiersAndFirstName: RawUnexpectedNodesSyntax? = nil,
     firstName: RawTokenSyntax?,
     _ unexpectedBetweenFirstNameAndSecondName: RawUnexpectedNodesSyntax? = nil,
     secondName: RawTokenSyntax?,
@@ -7316,28 +7314,26 @@ public struct RawFunctionParameterSyntax: RawSyntaxNodeProtocol, RawSyntaxToSynt
     arena: __shared SyntaxArena
   ) {
     let raw = RawSyntax.makeLayout(
-      kind: .functionParameter, uninitializedCount: 20, arena: arena) { layout in
+      kind: .functionParameter, uninitializedCount: 18, arena: arena) { layout in
       layout.initialize(repeating: nil)
       layout[0] = unexpectedBeforeAttributes?.raw
       layout[1] = attributes?.raw
-      layout[2] = unexpectedBetweenAttributesAndIsolatedToken?.raw
-      layout[3] = isolatedToken?.raw
-      layout[4] = unexpectedBetweenIsolatedTokenAndConstToken?.raw
-      layout[5] = constToken?.raw
-      layout[6] = unexpectedBetweenConstTokenAndFirstName?.raw
-      layout[7] = firstName?.raw
-      layout[8] = unexpectedBetweenFirstNameAndSecondName?.raw
-      layout[9] = secondName?.raw
-      layout[10] = unexpectedBetweenSecondNameAndColon?.raw
-      layout[11] = colon?.raw
-      layout[12] = unexpectedBetweenColonAndType?.raw
-      layout[13] = type?.raw
-      layout[14] = unexpectedBetweenTypeAndEllipsis?.raw
-      layout[15] = ellipsis?.raw
-      layout[16] = unexpectedBetweenEllipsisAndDefaultArgument?.raw
-      layout[17] = defaultArgument?.raw
-      layout[18] = unexpectedBetweenDefaultArgumentAndTrailingComma?.raw
-      layout[19] = trailingComma?.raw
+      layout[2] = unexpectedBetweenAttributesAndModifiers?.raw
+      layout[3] = modifiers?.raw
+      layout[4] = unexpectedBetweenModifiersAndFirstName?.raw
+      layout[5] = firstName?.raw
+      layout[6] = unexpectedBetweenFirstNameAndSecondName?.raw
+      layout[7] = secondName?.raw
+      layout[8] = unexpectedBetweenSecondNameAndColon?.raw
+      layout[9] = colon?.raw
+      layout[10] = unexpectedBetweenColonAndType?.raw
+      layout[11] = type?.raw
+      layout[12] = unexpectedBetweenTypeAndEllipsis?.raw
+      layout[13] = ellipsis?.raw
+      layout[14] = unexpectedBetweenEllipsisAndDefaultArgument?.raw
+      layout[15] = defaultArgument?.raw
+      layout[16] = unexpectedBetweenDefaultArgumentAndTrailingComma?.raw
+      layout[17] = trailingComma?.raw
     }
     self.init(raw: raw)
   }
@@ -7348,59 +7344,53 @@ public struct RawFunctionParameterSyntax: RawSyntaxNodeProtocol, RawSyntaxToSynt
   public var attributes: RawAttributeListSyntax? {
     layoutView.children[1].map(RawAttributeListSyntax.init(raw:))
   }
-  public var unexpectedBetweenAttributesAndIsolatedToken: RawUnexpectedNodesSyntax? {
+  public var unexpectedBetweenAttributesAndModifiers: RawUnexpectedNodesSyntax? {
     layoutView.children[2].map(RawUnexpectedNodesSyntax.init(raw:))
   }
-  public var isolatedToken: RawTokenSyntax? {
-    layoutView.children[3].map(RawTokenSyntax.init(raw:))
+  public var modifiers: RawModifierListSyntax? {
+    layoutView.children[3].map(RawModifierListSyntax.init(raw:))
   }
-  public var unexpectedBetweenIsolatedTokenAndConstToken: RawUnexpectedNodesSyntax? {
+  public var unexpectedBetweenModifiersAndFirstName: RawUnexpectedNodesSyntax? {
     layoutView.children[4].map(RawUnexpectedNodesSyntax.init(raw:))
   }
-  public var constToken: RawTokenSyntax? {
-    layoutView.children[5].map(RawTokenSyntax.init(raw:))
-  }
-  public var unexpectedBetweenConstTokenAndFirstName: RawUnexpectedNodesSyntax? {
-    layoutView.children[6].map(RawUnexpectedNodesSyntax.init(raw:))
-  }
   public var firstName: RawTokenSyntax? {
-    layoutView.children[7].map(RawTokenSyntax.init(raw:))
+    layoutView.children[5].map(RawTokenSyntax.init(raw:))
   }
   public var unexpectedBetweenFirstNameAndSecondName: RawUnexpectedNodesSyntax? {
-    layoutView.children[8].map(RawUnexpectedNodesSyntax.init(raw:))
+    layoutView.children[6].map(RawUnexpectedNodesSyntax.init(raw:))
   }
   public var secondName: RawTokenSyntax? {
-    layoutView.children[9].map(RawTokenSyntax.init(raw:))
+    layoutView.children[7].map(RawTokenSyntax.init(raw:))
   }
   public var unexpectedBetweenSecondNameAndColon: RawUnexpectedNodesSyntax? {
-    layoutView.children[10].map(RawUnexpectedNodesSyntax.init(raw:))
+    layoutView.children[8].map(RawUnexpectedNodesSyntax.init(raw:))
   }
   public var colon: RawTokenSyntax? {
-    layoutView.children[11].map(RawTokenSyntax.init(raw:))
+    layoutView.children[9].map(RawTokenSyntax.init(raw:))
   }
   public var unexpectedBetweenColonAndType: RawUnexpectedNodesSyntax? {
-    layoutView.children[12].map(RawUnexpectedNodesSyntax.init(raw:))
+    layoutView.children[10].map(RawUnexpectedNodesSyntax.init(raw:))
   }
   public var type: RawTypeSyntax? {
-    layoutView.children[13].map(RawTypeSyntax.init(raw:))
+    layoutView.children[11].map(RawTypeSyntax.init(raw:))
   }
   public var unexpectedBetweenTypeAndEllipsis: RawUnexpectedNodesSyntax? {
-    layoutView.children[14].map(RawUnexpectedNodesSyntax.init(raw:))
+    layoutView.children[12].map(RawUnexpectedNodesSyntax.init(raw:))
   }
   public var ellipsis: RawTokenSyntax? {
-    layoutView.children[15].map(RawTokenSyntax.init(raw:))
+    layoutView.children[13].map(RawTokenSyntax.init(raw:))
   }
   public var unexpectedBetweenEllipsisAndDefaultArgument: RawUnexpectedNodesSyntax? {
-    layoutView.children[16].map(RawUnexpectedNodesSyntax.init(raw:))
+    layoutView.children[14].map(RawUnexpectedNodesSyntax.init(raw:))
   }
   public var defaultArgument: RawInitializerClauseSyntax? {
-    layoutView.children[17].map(RawInitializerClauseSyntax.init(raw:))
+    layoutView.children[15].map(RawInitializerClauseSyntax.init(raw:))
   }
   public var unexpectedBetweenDefaultArgumentAndTrailingComma: RawUnexpectedNodesSyntax? {
-    layoutView.children[18].map(RawUnexpectedNodesSyntax.init(raw:))
+    layoutView.children[16].map(RawUnexpectedNodesSyntax.init(raw:))
   }
   public var trailingComma: RawTokenSyntax? {
-    layoutView.children[19].map(RawTokenSyntax.init(raw:))
+    layoutView.children[17].map(RawTokenSyntax.init(raw:))
   }
 }
 

Sources/SwiftSyntax/Raw/gyb_generated/RawSyntaxValidation.swift

@@ -987,27 +987,25 @@ func validateLayout(layout: RawSyntaxBuffer, as kind: SyntaxKind) {
     _verify(layout[3], as: RawExprSyntax.self)
     break
   case .functionParameter:
-    assert(layout.count == 20)
+    assert(layout.count == 18)
     _verify(layout[0], as: RawUnexpectedNodesSyntax?.self)
     _verify(layout[1], as: RawAttributeListSyntax?.self)
     _verify(layout[2], as: RawUnexpectedNodesSyntax?.self)
-    _verify(layout[3], as: RawTokenSyntax?.self)
+    _verify(layout[3], as: RawModifierListSyntax?.self)
     _verify(layout[4], as: RawUnexpectedNodesSyntax?.self)
     _verify(layout[5], as: RawTokenSyntax?.self)
     _verify(layout[6], as: RawUnexpectedNodesSyntax?.self)
     _verify(layout[7], as: RawTokenSyntax?.self)
     _verify(layout[8], as: RawUnexpectedNodesSyntax?.self)
     _verify(layout[9], as: RawTokenSyntax?.self)
     _verify(layout[10], as: RawUnexpectedNodesSyntax?.self)
-    _verify(layout[11], as: RawTokenSyntax?.self)
+    _verify(layout[11], as: RawTypeSyntax?.self)
     _verify(layout[12], as: RawUnexpectedNodesSyntax?.self)
-    _verify(layout[13], as: RawTypeSyntax?.self)
+    _verify(layout[13], as: RawTokenSyntax?.self)
     _verify(layout[14], as: RawUnexpectedNodesSyntax?.self)
-    _verify(layout[15], as: RawTokenSyntax?.self)
+    _verify(layout[15], as: RawInitializerClauseSyntax?.self)
     _verify(layout[16], as: RawUnexpectedNodesSyntax?.self)
-    _verify(layout[17], as: RawInitializerClauseSyntax?.self)
-    _verify(layout[18], as: RawUnexpectedNodesSyntax?.self)
-    _verify(layout[19], as: RawTokenSyntax?.self)
+    _verify(layout[17], as: RawTokenSyntax?.self)
     break
   case .modifierList:
     for element in layout {

Sources/SwiftSyntax/gyb_generated/SyntaxFactory.swift

@@ -3136,15 +3136,13 @@ public enum SyntaxFactory {
     return InitializerClauseSyntax(data)
   }
   @available(*, deprecated, message: "Use initializer on FunctionParameterSyntax")
-  public static func makeFunctionParameter(_ unexpectedBeforeAttributes: UnexpectedNodesSyntax? = nil, attributes: AttributeListSyntax?, _ unexpectedBetweenAttributesAndIsolatedToken: UnexpectedNodesSyntax? = nil, isolatedToken: TokenSyntax?, _ unexpectedBetweenIsolatedTokenAndConstToken: UnexpectedNodesSyntax? = nil, constToken: TokenSyntax?, _ unexpectedBetweenConstTokenAndFirstName: UnexpectedNodesSyntax? = nil, firstName: TokenSyntax?, _ unexpectedBetweenFirstNameAndSecondName: UnexpectedNodesSyntax? = nil, secondName: TokenSyntax?, _ unexpectedBetweenSecondNameAndColon: UnexpectedNodesSyntax? = nil, colon: TokenSyntax?, _ unexpectedBetweenColonAndType: UnexpectedNodesSyntax? = nil, type: TypeSyntax?, _ unexpectedBetweenTypeAndEllipsis: UnexpectedNodesSyntax? = nil, ellipsis: TokenSyntax?, _ unexpectedBetweenEllipsisAndDefaultArgument: UnexpectedNodesSyntax? = nil, defaultArgument: InitializerClauseSyntax?, _ unexpectedBetweenDefaultArgumentAndTrailingComma: UnexpectedNodesSyntax? = nil, trailingComma: TokenSyntax?) -> FunctionParameterSyntax {
+  public static func makeFunctionParameter(_ unexpectedBeforeAttributes: UnexpectedNodesSyntax? = nil, attributes: AttributeListSyntax?, _ unexpectedBetweenAttributesAndModifiers: UnexpectedNodesSyntax? = nil, modifiers: ModifierListSyntax?, _ unexpectedBetweenModifiersAndFirstName: UnexpectedNodesSyntax? = nil, firstName: TokenSyntax?, _ unexpectedBetweenFirstNameAndSecondName: UnexpectedNodesSyntax? = nil, secondName: TokenSyntax?, _ unexpectedBetweenSecondNameAndColon: UnexpectedNodesSyntax? = nil, colon: TokenSyntax?, _ unexpectedBetweenColonAndType: UnexpectedNodesSyntax? = nil, type: TypeSyntax?, _ unexpectedBetweenTypeAndEllipsis: UnexpectedNodesSyntax? = nil, ellipsis: TokenSyntax?, _ unexpectedBetweenEllipsisAndDefaultArgument: UnexpectedNodesSyntax? = nil, defaultArgument: InitializerClauseSyntax?, _ unexpectedBetweenDefaultArgumentAndTrailingComma: UnexpectedNodesSyntax? = nil, trailingComma: TokenSyntax?) -> FunctionParameterSyntax {
     let layout: [RawSyntax?] = [
       unexpectedBeforeAttributes?.raw,
       attributes?.raw,
-      unexpectedBetweenAttributesAndIsolatedToken?.raw,
-      isolatedToken?.raw,
-      unexpectedBetweenIsolatedTokenAndConstToken?.raw,
-      constToken?.raw,
-      unexpectedBetweenConstTokenAndFirstName?.raw,
+      unexpectedBetweenAttributesAndModifiers?.raw,
+      modifiers?.raw,
+      unexpectedBetweenModifiersAndFirstName?.raw,
       firstName?.raw,
       unexpectedBetweenFirstNameAndSecondName?.raw,
       secondName?.raw,
@@ -3187,8 +3185,6 @@ public enum SyntaxFactory {
       nil,
       nil,
       nil,
-      nil,
-      nil,
     ], arena: .default))
     return FunctionParameterSyntax(data)
   }