Add keypath method and initializer syntax under an experimental feature flag keypathWithMethodMembers

CodeGeneration/Sources/SyntaxSupport/ExperimentalFeatures.swift

@@ -22,6 +22,7 @@ public enum ExperimentalFeature: String, CaseIterable {
   case valueGenerics
   case abiAttribute
   case unsafeExpression
+  case keypathWithMethodMembers
 
   /// The name of the feature as it is written in the compiler's `Features.def` file.
   public var featureName: String {
@@ -44,6 +45,8 @@ public enum ExperimentalFeature: String, CaseIterable {
       return "ABIAttribute"
     case .unsafeExpression:
       return "WarnUnsafe"
+    case .keypathWithMethodMembers:
+      return "KeypathWithMethodMembers"
     }
   }
 
@@ -68,6 +71,8 @@ public enum ExperimentalFeature: String, CaseIterable {
       return "@abi attribute"
     case .unsafeExpression:
       return "'unsafe' expression"
+    case .keypathWithMethodMembers:
+      return "keypaths with method members"
     }
   }
 

CodeGeneration/Sources/SyntaxSupport/ExprNodes.swift

@@ -1209,6 +1209,11 @@ public let EXPR_NODES: [Node] = [
             name: "property",
             kind: .node(kind: .keyPathPropertyComponent)
           ),
+          Child(
+            name: "method",
+            kind: .node(kind: .keyPathMethodComponent),
+            experimentalFeature: .keypathWithMethodMembers
+          ),
           Child(
             name: "subscript",
             kind: .node(kind: .keyPathSubscriptComponent)
@@ -1313,6 +1318,33 @@ public let EXPR_NODES: [Node] = [
     ]
   ),
 
+  Node(
+    kind: .keyPathMethodComponent,
+    base: .syntax,
+    experimentalFeature: .keypathWithMethodMembers,
+    nameForDiagnostics: "key path method component",
+    documentation: "A key path component like `.method()`, `.method(10)`, or `.method(val: 10)`.",
+    children: [
+      Child(
+        name: "declName",
+        kind: .node(kind: .declReferenceExpr)
+      ),
+      Child(
+        name: "leftParen",
+        kind: .token(choices: [.token(.leftParen)])
+      ),
+      Child(
+        name: "arguments",
+        kind: .collection(kind: .labeledExprList, collectionElementName: "Argument"),
+        nameForDiagnostics: "arguments"
+      ),
+      Child(
+        name: "rightParen",
+        kind: .token(choices: [.token(.rightParen)])
+      ),
+    ]
+  ),
+
   Node(
     kind: .macroExpansionExpr,
     base: .expr,

CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift

@@ -179,6 +179,7 @@ public enum SyntaxNodeKind: String, CaseIterable, IdentifierConvertible, TypeCon
   case keyPathOptionalComponent
   case keyPathPropertyComponent
   case keyPathSubscriptComponent
+  case keyPathMethodComponent
   case labeledExpr
   case labeledExprList
   case labeledSpecializeArgument

CodeGeneration/Tests/ValidateSyntaxNodes/ValidateSyntaxNodes.swift

@@ -549,6 +549,10 @@ class ValidateSyntaxNodes: XCTestCase {
           message: "could conform to trait 'Parenthesized' but does not"
         ),
         ValidationFailure(node: .lifetimeTypeSpecifier, message: "could conform to trait 'Parenthesized' but does not"),
+        ValidationFailure(
+          node: .keyPathMethodComponent,
+          message: "could conform to trait 'Parenthesized' but does not"
+        ),
       ]
     )
   }

Sources/SwiftParser/Expressions.swift

@@ -10,11 +10,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if compiler(>=6)
-@_spi(RawSyntax) internal import SwiftSyntax
+#if swift(>=6)
+@_spi(RawSyntax) @_spi(ExperimentalLanguageFeatures) internal import SwiftSyntax
+#else
+#if swift(>=5.8)
+@_spi(RawSyntax) @_spi(ExperimentalLanguageFeatures) import SwiftSyntax
 #else
 @_spi(RawSyntax) import SwiftSyntax
 #endif
+#endif
 
 extension TokenConsumer {
   mutating func atStartOfExpression() -> Bool {
@@ -1103,11 +1107,54 @@ extension Parser {
         continue
       }
 
-      // Check for a .name or .1 suffix.
+      // Check for a .name, .1, .name(), .name("Kiwi"), .name(fruit:),
+      // .name(_:), .name(fruit: "Kiwi) suffix.
       if self.at(.period) {
         let (unexpectedPeriod, period, declName, generics) = parseDottedExpressionSuffix(
           previousNode: components.last?.raw ?? rootType?.raw ?? backslash.raw
         )
+
+        // If fully applied method component, parse as a keypath method.
+        if self.experimentalFeatures.contains(.keypathWithMethodMembers)
+          && self.at(.leftParen)
+        {
+          var (unexpectedBeforeLParen, leftParen) = self.expect(.leftParen)
+          if let generics = generics {
+            unexpectedBeforeLParen = RawUnexpectedNodesSyntax(
+              (unexpectedBeforeLParen?.elements ?? []) + [RawSyntax(generics)],
+              arena: self.arena
+            )
+          }
+          let args = self.parseArgumentListElements(
+            pattern: pattern,
+            allowTrailingComma: true
+          )
+          let (unexpectedBeforeRParen, rightParen) = self.expect(.rightParen)
+
+          components.append(
+            RawKeyPathComponentSyntax(
+              unexpectedPeriod,
+              period: period,
+              component: .method(
+                RawKeyPathMethodComponentSyntax(
+                  declName: declName,
+                  unexpectedBeforeLParen,
+                  leftParen: leftParen,
+                  arguments: RawLabeledExprListSyntax(
+                    elements: args,
+                    arena: self.arena
+                  ),
+                  unexpectedBeforeRParen,
+                  rightParen: rightParen,
+                  arena: self.arena
+                )
+              ),
+              arena: self.arena
+            )
+          )
+          continue
+        }
+        // Else, parse as a property.
         components.append(
           RawKeyPathComponentSyntax(
             unexpectedPeriod,
@@ -1128,7 +1175,6 @@ extension Parser {
       // No more postfix expressions.
       break
     }
-
     return RawKeyPathExprSyntax(
       unexpectedBeforeBackslash,
       backslash: backslash,

Sources/SwiftParser/generated/ExperimentalFeatures.swift

@@ -51,6 +51,9 @@ extension Parser.ExperimentalFeatures {
   /// Whether to enable the parsing of 'unsafe' expression.
   public static let unsafeExpression = Self (rawValue: 1 << 8)
 
+  /// Whether to enable the parsing of keypaths with method members.
+  public static let keypathWithMethodMembers = Self (rawValue: 1 << 9)
+
   /// Creates a new value representing the experimental feature with the
   /// given name, or returns nil if the name is not recognized.
   public init?(name: String) {
@@ -73,6 +76,8 @@ extension Parser.ExperimentalFeatures {
       self = .abiAttribute
     case "WarnUnsafe":
       self = .unsafeExpression
+    case "KeypathWithMethodMembers":
+      self = .keypathWithMethodMembers
     default:
       return nil
     }

Sources/SwiftParserDiagnostics/generated/ChildNameForDiagnostics.swift

@@ -206,6 +206,8 @@ private func childNameForDiagnostics(_ keyPath: AnyKeyPath) -> String? {
     return "generic where clause"
   case \KeyPathExprSyntax.root:
     return "root"
+  case \KeyPathMethodComponentSyntax.arguments:
+    return "arguments"
   case \KeyPathSubscriptComponentSyntax.arguments:
     return "arguments"
   case \LabeledExprSyntax.label:

Sources/SwiftParserDiagnostics/generated/SyntaxKindNameForDiagnostics.swift

@@ -243,6 +243,8 @@ extension SyntaxKind {
       return "key path component"
     case .keyPathExpr:
       return "key path"
+    case .keyPathMethodComponent:
+      return "key path method component"
     case .keyPathOptionalComponent:
       return "key path optional component"
     case .keyPathPropertyComponent:

Sources/SwiftSyntax/generated/ChildNameForKeyPath.swift

@@ -1901,6 +1901,24 @@ public func childName(_ keyPath: AnyKeyPath) -> String? {
     return "components"
   case \KeyPathExprSyntax.unexpectedAfterComponents:
     return "unexpectedAfterComponents"
+  case \KeyPathMethodComponentSyntax.unexpectedBeforeDeclName:
+    return "unexpectedBeforeDeclName"
+  case \KeyPathMethodComponentSyntax.declName:
+    return "declName"
+  case \KeyPathMethodComponentSyntax.unexpectedBetweenDeclNameAndLeftParen:
+    return "unexpectedBetweenDeclNameAndLeftParen"
+  case \KeyPathMethodComponentSyntax.leftParen:
+    return "leftParen"
+  case \KeyPathMethodComponentSyntax.unexpectedBetweenLeftParenAndArguments:
+    return "unexpectedBetweenLeftParenAndArguments"
+  case \KeyPathMethodComponentSyntax.arguments:
+    return "arguments"
+  case \KeyPathMethodComponentSyntax.unexpectedBetweenArgumentsAndRightParen:
+    return "unexpectedBetweenArgumentsAndRightParen"
+  case \KeyPathMethodComponentSyntax.rightParen:
+    return "rightParen"
+  case \KeyPathMethodComponentSyntax.unexpectedAfterRightParen:
+    return "unexpectedAfterRightParen"
   case \KeyPathOptionalComponentSyntax.unexpectedBeforeQuestionOrExclamationMark:
     return "unexpectedBeforeQuestionOrExclamationMark"
   case \KeyPathOptionalComponentSyntax.questionOrExclamationMark:

Sources/SwiftSyntax/generated/SyntaxAnyVisitor.swift

@@ -1294,6 +1294,16 @@ open class SyntaxAnyVisitor: SyntaxVisitor {
     visitAnyPost(node._syntaxNode)
   }
 
+  @_spi(ExperimentalLanguageFeatures)
+  override open func visit(_ node: KeyPathMethodComponentSyntax) -> SyntaxVisitorContinueKind {
+    return visitAny(node._syntaxNode)
+  }
+
+  @_spi(ExperimentalLanguageFeatures)
+  override open func visitPost(_ node: KeyPathMethodComponentSyntax) {
+    visitAnyPost(node._syntaxNode)
+  }
+
   override open func visit(_ node: KeyPathOptionalComponentSyntax) -> SyntaxVisitorContinueKind {
     return visitAny(node._syntaxNode)
   }

Sources/SwiftSyntax/generated/SyntaxBaseNodes.swift

@@ -1672,6 +1672,7 @@ extension Syntax {
       .node(KeyPathComponentListSyntax.self),
       .node(KeyPathComponentSyntax.self),
       .node(KeyPathExprSyntax.self),
+      .node(KeyPathMethodComponentSyntax.self),
       .node(KeyPathOptionalComponentSyntax.self),
       .node(KeyPathPropertyComponentSyntax.self),
       .node(KeyPathSubscriptComponentSyntax.self),

Sources/SwiftSyntax/generated/SyntaxEnum.swift

@@ -172,6 +172,8 @@ public enum SyntaxEnum: Sendable {
   case keyPathComponentList(KeyPathComponentListSyntax)
   case keyPathComponent(KeyPathComponentSyntax)
   case keyPathExpr(KeyPathExprSyntax)
+  @_spi(ExperimentalLanguageFeatures)
+  case keyPathMethodComponent(KeyPathMethodComponentSyntax)
   case keyPathOptionalComponent(KeyPathOptionalComponentSyntax)
   case keyPathPropertyComponent(KeyPathPropertyComponentSyntax)
   case keyPathSubscriptComponent(KeyPathSubscriptComponentSyntax)
@@ -625,6 +627,8 @@ extension Syntax {
       return .keyPathComponent(KeyPathComponentSyntax(self)!)
     case .keyPathExpr:
       return .keyPathExpr(KeyPathExprSyntax(self)!)
+    case .keyPathMethodComponent:
+      return .keyPathMethodComponent(KeyPathMethodComponentSyntax(self)!)
     case .keyPathOptionalComponent:
       return .keyPathOptionalComponent(KeyPathOptionalComponentSyntax(self)!)
     case .keyPathPropertyComponent:

Sources/SwiftSyntax/generated/SyntaxKind.swift

@@ -172,6 +172,8 @@ public enum SyntaxKind: Sendable {
   case keyPathComponentList
   case keyPathComponent
   case keyPathExpr
+  @_spi(ExperimentalLanguageFeatures)
+  case keyPathMethodComponent
   case keyPathOptionalComponent
   case keyPathPropertyComponent
   case keyPathSubscriptComponent
@@ -750,6 +752,8 @@ public enum SyntaxKind: Sendable {
       return KeyPathComponentSyntax.self
     case .keyPathExpr:
       return KeyPathExprSyntax.self
+    case .keyPathMethodComponent:
+      return KeyPathMethodComponentSyntax.self
     case .keyPathOptionalComponent:
       return KeyPathOptionalComponentSyntax.self
     case .keyPathPropertyComponent:

Sources/SwiftSyntax/generated/SyntaxRewriter.swift

@@ -1179,6 +1179,14 @@ open class SyntaxRewriter {
     return ExprSyntax(KeyPathExprSyntax(unsafeCasting: visitChildren(node._syntaxNode)))
   }
 
+  /// Visit a `KeyPathMethodComponentSyntax`.
+  ///   - Parameter node: the node that is being visited
+  ///   - Returns: the rewritten node
+  @_spi(ExperimentalLanguageFeatures)
+  open func visit(_ node: KeyPathMethodComponentSyntax) -> KeyPathMethodComponentSyntax {
+    return KeyPathMethodComponentSyntax(unsafeCasting: visitChildren(node._syntaxNode))
+  }
+
   /// Visit a ``KeyPathOptionalComponentSyntax``.
   ///   - Parameter node: the node that is being visited
   ///   - Returns: the rewritten node
@@ -2918,6 +2926,11 @@ open class SyntaxRewriter {
     Syntax(visit(KeyPathExprSyntax(unsafeCasting: node)))
   }
 
+  @inline(never)
+  private func visitKeyPathMethodComponentSyntaxImpl(_ node: Syntax) -> Syntax {
+    Syntax(visit(KeyPathMethodComponentSyntax(unsafeCasting: node)))
+  }
+
   @inline(never)
   private func visitKeyPathOptionalComponentSyntaxImpl(_ node: Syntax) -> Syntax {
     Syntax(visit(KeyPathOptionalComponentSyntax(unsafeCasting: node)))
@@ -3914,6 +3927,8 @@ open class SyntaxRewriter {
       return self.visitKeyPathComponentSyntaxImpl(_:)
     case .keyPathExpr:
       return self.visitKeyPathExprSyntaxImpl(_:)
+    case .keyPathMethodComponent:
+      return self.visitKeyPathMethodComponentSyntaxImpl(_:)
     case .keyPathOptionalComponent:
       return self.visitKeyPathOptionalComponentSyntaxImpl(_:)
     case .keyPathPropertyComponent:
@@ -4496,6 +4511,8 @@ open class SyntaxRewriter {
       return visitKeyPathComponentSyntaxImpl(node)
     case .keyPathExpr:
       return visitKeyPathExprSyntaxImpl(node)
+    case .keyPathMethodComponent:
+      return visitKeyPathMethodComponentSyntaxImpl(node)
     case .keyPathOptionalComponent:
       return visitKeyPathOptionalComponentSyntaxImpl(node)
     case .keyPathPropertyComponent:

Sources/SwiftSyntax/generated/SyntaxVisitor.swift

@@ -1888,6 +1888,20 @@ open class SyntaxVisitor {
   open func visitPost(_ node: KeyPathExprSyntax) {
   }
 
+  /// Visiting `KeyPathMethodComponentSyntax` specifically.
+  ///   - Parameter node: the node we are visiting.
+  ///   - Returns: how should we continue visiting.
+  @_spi(ExperimentalLanguageFeatures)
+  open func visit(_ node: KeyPathMethodComponentSyntax) -> SyntaxVisitorContinueKind {
+    return .visitChildren
+  }
+
+  /// The function called after visiting `KeyPathMethodComponentSyntax` and its descendants.
+  ///   - node: the node we just finished visiting.
+  @_spi(ExperimentalLanguageFeatures)
+  open func visitPost(_ node: KeyPathMethodComponentSyntax) {
+  }
+
   /// Visiting ``KeyPathOptionalComponentSyntax`` specifically.
   ///   - Parameter node: the node we are visiting.
   ///   - Returns: how should we continue visiting.
@@ -4733,6 +4747,14 @@ open class SyntaxVisitor {
     visitPost(KeyPathExprSyntax(unsafeCasting: node))
   }
 
+  @inline(never)
+  private func visitKeyPathMethodComponentSyntaxImpl(_ node: Syntax) {
+    if visit(KeyPathMethodComponentSyntax(unsafeCasting: node)) == .visitChildren {
+      visitChildren(node)
+    }
+    visitPost(KeyPathMethodComponentSyntax(unsafeCasting: node))
+  }
+
   @inline(never)
   private func visitKeyPathOptionalComponentSyntaxImpl(_ node: Syntax) {
     if visit(KeyPathOptionalComponentSyntax(unsafeCasting: node)) == .visitChildren {
@@ -6125,6 +6147,8 @@ open class SyntaxVisitor {
       return self.visitKeyPathComponentSyntaxImpl(_:)
     case .keyPathExpr:
       return self.visitKeyPathExprSyntaxImpl(_:)
+    case .keyPathMethodComponent:
+      return self.visitKeyPathMethodComponentSyntaxImpl(_:)
     case .keyPathOptionalComponent:
       return self.visitKeyPathOptionalComponentSyntaxImpl(_:)
     case .keyPathPropertyComponent:
@@ -6707,6 +6731,8 @@ open class SyntaxVisitor {
       self.visitKeyPathComponentSyntaxImpl(node)
     case .keyPathExpr:
       self.visitKeyPathExprSyntaxImpl(node)
+    case .keyPathMethodComponent:
+      self.visitKeyPathMethodComponentSyntaxImpl(node)
     case .keyPathOptionalComponent:
       self.visitKeyPathOptionalComponentSyntaxImpl(node)
     case .keyPathPropertyComponent: