Re-model type specifiers and allow multiple specifiers on a type

The previous design of having a single specifier on an `AttributedTypeSyntax` no longer sufficied because a function paramter type can have multiple specifiers, such as `borrowing _const String`. Re-design the way type specifiers are represented by introducing type nodes for every specifier kind: `ConstTypeSyntax` for `_const`, `IsolatedTypeSyntax` for `isolated`, `LifetimeDependenceParameterSyntax` for `_copy(parameterName)` etc., `LifetimeDependenceTypeSyntax` for `inout`, `__shared` etc., and `ResultDependsOnTypeSyntax` for `_resultDependsOn`.

rdar://118125715

Author: ahoppen

CodeGeneration/Sources/SyntaxSupport/KeywordSpec.swift

@@ -87,7 +87,9 @@ public enum Keyword: CaseIterable {
   case _Class
   case _compilerInitialized
   case _const
+  case _consume
   case _consuming
+  case _copy
   case _documentation
   case _dynamicReplacement
   case _effects
@@ -98,6 +100,7 @@ public enum Keyword: CaseIterable {
   case _local
   case _modify
   case _move
+  case _mutate
   case _mutating
   case _NativeClass
   case _NativeRefCountedObject
@@ -307,6 +310,8 @@ public enum Keyword: CaseIterable {
       return KeywordSpec("_backDeploy")
     case ._borrow:
       return KeywordSpec("_borrow")
+    case ._borrowing:
+      return KeywordSpec("_borrowing", experimentalFeature: .referenceBindings)
     case ._BridgeObject:
       return KeywordSpec("_BridgeObject")
     case ._cdecl:
@@ -317,6 +322,12 @@ public enum Keyword: CaseIterable {
       return KeywordSpec("_compilerInitialized")
     case ._const:
       return KeywordSpec("_const")
+    case ._consume:
+      return KeywordSpec("_consume", experimentalFeature: .nonescapableTypes)
+    case ._consuming:
+      return KeywordSpec("_consuming", experimentalFeature: .referenceBindings)
+    case ._copy:
+      return KeywordSpec("_copy", experimentalFeature: .nonescapableTypes)
     case ._documentation:
       return KeywordSpec("_documentation")
     case ._dynamicReplacement:
@@ -337,6 +348,10 @@ public enum Keyword: CaseIterable {
       return KeywordSpec("_modify")
     case ._move:
       return KeywordSpec("_move")
+    case ._mutating:
+      return KeywordSpec("_mutating", experimentalFeature: .referenceBindings)
+    case ._mutate:
+      return KeywordSpec("_mutate", experimentalFeature: .nonescapableTypes)
     case ._NativeClass:
       return KeywordSpec("_NativeClass")
     case ._NativeRefCountedObject:
@@ -722,12 +737,6 @@ public enum Keyword: CaseIterable {
       return KeywordSpec("wrt")
     case .yield:
       return KeywordSpec("yield")
-    case ._borrowing:
-      return KeywordSpec("_borrowing", experimentalFeature: .referenceBindings)
-    case ._consuming:
-      return KeywordSpec("_consuming", experimentalFeature: .referenceBindings)
-    case ._mutating:
-      return KeywordSpec("_mutating", experimentalFeature: .referenceBindings)
     }
   }
 }

CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift

@@ -75,6 +75,7 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case conditionElement
   case conditionElementList
   case conformanceRequirement
+  case constType
   case consumeExpr
   case continueStmt
   case conventionAttributeArguments
@@ -99,8 +100,8 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case dictionaryExpr
   case dictionaryType
   case differentiabilityArgument
-  case differentiabilityArguments
   case differentiabilityArgumentList
+  case differentiabilityArguments
   case differentiabilityWithRespectToArgument
   case differentiableAttributeArguments
   case discardAssignmentExpr
@@ -170,6 +171,7 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case inOutExpr
   case integerLiteralExpr
   case isExpr
+  case isolatedType
   case isTypePattern
   case keyPathComponent
   case keyPathComponentList
@@ -182,6 +184,10 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case labeledSpecializeArgument
   case labeledStmt
   case layoutRequirement
+  case lifetimeDependenceParameter
+  case lifetimeDependenceParameterList
+  case lifetimeDependenceType
+  case lifetimeSpecifiedType
   case macroDecl
   case macroExpansionDecl
   case macroExpansionExpr
@@ -240,18 +246,19 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case protocolDecl
   case regexLiteralExpr
   case repeatStmt
+  case resultDependsOnType
   case returnClause
   case returnStmt
   case sameTypeRequirement
   case sequenceExpr
+  case simpleStringLiteralExpr
+  case simpleStringLiteralSegmentList
   case someOrAnyType
   case sourceFile
   case specializeAttributeArgumentList
   case specializeAvailabilityArgument
   case specializeTargetFunctionArgument
   case stmt
-  case simpleStringLiteralExpr
-  case simpleStringLiteralSegmentList
   case stringLiteralExpr
   case stringLiteralSegmentList
   case stringSegment
@@ -299,10 +306,10 @@ public enum SyntaxNodeKind: String, CaseIterable {
   case whereClause
   case whileStmt
   case wildcardPattern
-  case yieldStmt
   case yieldedExpression
-  case yieldedExpressionsClause
   case yieldedExpressionList
+  case yieldedExpressionsClause
+  case yieldStmt
 
   // Nodes that have special handling throughout the codebase
 

CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift

@@ -42,21 +42,6 @@ public let TYPE_NODES: [Node] = [
       "WithAttributes"
     ],
     children: [
-      Child(
-        name: "specifier",
-        kind: .token(choices: [
-          .keyword(.inout),
-          .keyword(.__shared),
-          .keyword(.__owned),
-          .keyword(.isolated),
-          .keyword(._const),
-          .keyword(.borrowing),
-          .keyword(.consuming),
-          .keyword(.transferring),
-          .keyword(._resultDependsOn),
-        ]),
-        isOptional: true
-      ),
       Child(
         name: "attributes",
         kind: .collection(kind: .attributeList, collectionElementName: "Attribute", defaultsToEmpty: true)
@@ -116,6 +101,22 @@ public let TYPE_NODES: [Node] = [
     ]
   ),
 
+  Node(
+    kind: .constType,
+    base: .type,
+    nameForDiagnostics: nil,
+    documentation: """
+      TODO: What does _const mean?
+      """,
+    children: [
+      Child(
+        name: "constKeyword",
+        kind: .token(choices: [.keyword(._const)])
+      ),
+      Child(name: "baseType", kind: .node(kind: .type)),
+    ]
+  ),
+
   Node(
     kind: .someOrAnyType,
     base: .type,
@@ -267,6 +268,103 @@ public let TYPE_NODES: [Node] = [
     ]
   ),
 
+  Node(
+    kind: .isolatedType,
+    base: .type,
+    nameForDiagnostics: nil,
+    documentation: """
+      The type of a function parameter that specifies that the paramter is isolated to (TODO what is the paramter isolated to?)
+      """,
+    children: [
+      Child(
+        name: "isolatedKeyword",
+        kind: .token(choices: [.keyword(.isolated)])
+      ),
+      Child(name: "baseType", kind: .node(kind: .type)),
+    ]
+  ),
+
+  Node(
+    kind: .lifetimeDependenceType,
+    base: .type,
+    experimentalFeature: .nonescapableTypes,
+    nameForDiagnostics: nil,
+    documentation: """
+      A function return type that specifies which parameters its lifetime depends on (TODO: Is this even correct?)
+      """,
+    children: [
+      Child(
+        name: "lifetimeDependenceSpecifier",
+        kind: .token(choices: [.keyword(._copy), .keyword(._consume), .keyword(._borrow), .keyword(._mutate)])
+      ),
+      Child(
+        name: "leftParen",
+        kind: .token(choices: [.token(.leftParen)])
+      ),
+      Child(
+        name: "parameters",
+        deprecatedName: "arguments",
+        kind: .collection(kind: .lifetimeDependenceParameterList, collectionElementName: "Parameter")
+      ),
+      Child(
+        name: "rightParen",
+        kind: .token(choices: [.token(.rightParen)])
+      ),
+      Child(name: "baseType", kind: .node(kind: .type)),
+    ]
+  ),
+
+  // TODO: Should these be called parameters or arguments?
+  Node(
+    kind: .lifetimeDependenceParameter,
+    base: .syntax,
+    experimentalFeature: .nonescapableTypes,
+    nameForDiagnostics: nil,
+    documentation: """
+      A parameter to a lifetime dependence annotation to a type.
+
+      ### Examples
+       - `x` in `_mutate(x)`
+       - `1` in `_borrow(1)` TODO: What does this even mean?
+       - `self` in `_consume(self)`
+      """,
+    traits: [
+      "WithTrailingComma"
+    ],
+    children: [
+      Child(name: "parameter", kind: .token(choices: [.token(.identifier), .token(.integerLiteral), .keyword(.`self`)])),
+      Child(
+        name: "trailingComma",
+        kind: .token(choices: [.token(.comma)]),
+        isOptional: true
+      ),
+    ]
+  ),
+
+  Node(
+    kind: .lifetimeDependenceParameterList,
+    base: .syntaxCollection,
+    experimentalFeature: .nonescapableTypes,
+    nameForDiagnostics: nil,
+    elementChoices: [.lifetimeDependenceParameter]
+  ),
+
+  Node(
+    kind: .lifetimeSpecifiedType,
+    base: .type,
+    nameForDiagnostics: nil,
+    documentation: """
+      The type of a function parameter that explicitly specifies the lifetime transfer as `borrowing`, `transferring`, or `consuming`.
+      """,
+    children: [
+      Child(
+        name: "lifetimeSpecifier",
+        kind: .token(choices: [.keyword(.__shared), .keyword(.__owned), .keyword(.borrowing), .keyword(.transferring), .keyword(.consuming), .keyword(.inout)])
+      ),
+      Child(name: "baseType", kind: .node(kind: .type)),
+    ]
+  ),
+
   Node(
     kind: .memberType,
     base: .type,
@@ -424,6 +522,23 @@ public let TYPE_NODES: [Node] = [
     ]
   ),
 
+  Node(
+    kind: .resultDependsOnType,
+    base: .type,
+    experimentalFeature: .nonescapableTypes,
+    nameForDiagnostics: nil,
+    documentation: """
+      TODO: What does _resultDependsOn mean?
+      """,
+    children: [
+      Child(
+        name: "resultDependsOnKeyword",
+        kind: .token(choices: [.keyword(._resultDependsOn)])
+      ),
+      Child(name: "baseType", kind: .node(kind: .type)),
+    ]
+  ),
+
   Node(
     kind: .tupleTypeElementList,
     base: .syntaxCollection,

CodeGeneration/Sources/generate-swift-syntax/templates/swiftsyntaxbuilder/ResultBuildersFile.swift

@@ -18,7 +18,7 @@ import Utils
 let resultBuildersFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
   DeclSyntax("import SwiftSyntax")
 
-  for node in SYNTAX_NODES.compactMap(\.collectionNode) {
+  for node in SYNTAX_NODES.compactMap(\.collectionNode) where node.experimentalFeature == nil {
     let type = SyntaxBuildableType(kind: .node(kind: node.kind))
 
     try! StructDeclSyntax(

CodeGeneration/Tests/ValidateSyntaxNodes/ValidateSyntaxNodes.swift

@@ -166,7 +166,7 @@ class ValidateSyntaxNodes: XCTestCase {
     }
     switch choice {
     case .keyword(let keyword):
-      let keywordName = keyword.spec.name
+      let keywordName = keyword.spec.name.dropPrefix("_")
 
       if child.isFollowedByColonToken(in: node) {
         if child.varOrCaseName.description != "\(keywordName)Label" {
@@ -289,11 +289,6 @@ class ValidateSyntaxNodes: XCTestCase {
         ),
 
         // MARK: Tokens that contain underscores
-        ValidationFailure(
-          node: .borrowExpr,
-          message: "child 'borrowKeyword' has a single keyword as its only token choice and should thus be named '_borrowKeyword'"
-            // _borrow is underscored and thus BorrowKeyword is the correct spelling
-        ),
         ValidationFailure(
           node: .conventionWitnessMethodAttributeArguments,
           message:
@@ -507,6 +502,7 @@ class ValidateSyntaxNodes: XCTestCase {
         ValidationFailure(node: .editorPlaceholderExpr, message: "could conform to trait 'MissingNode' but does not"),
         ValidationFailure(node: .enumCaseElement, message: "could conform to trait 'NamedDecl' but does not"),
         ValidationFailure(node: .genericParameter, message: "could conform to trait 'NamedDecl' but does not"),
+        ValidationFailure(node: .lifetimeDependenceType, message: "could conform to trait 'Parenthesized' but does not"),
         ValidationFailure(node: .precedenceGroupName, message: "could conform to trait 'NamedDecl' but does not"),
         ValidationFailure(node: .primaryAssociatedType, message: "could conform to trait 'NamedDecl' but does not"),
         ValidationFailure(node: .yieldedExpressionsClause, message: "could conform to trait 'Parenthesized' but does not"),
@@ -664,12 +660,17 @@ class ValidateSyntaxNodes: XCTestCase {
         ValidationFailure(node: .attributedType, message: "child 'baseType' should not end with 'Type'"),
         ValidationFailure(node: .conformanceRequirement, message: "child 'leftType' should not end with 'Type'"),
         ValidationFailure(node: .conformanceRequirement, message: "child 'rightType' should not end with 'Type'"),
+        ValidationFailure(node: .constType, message: "child 'baseType' should not end with 'Type'"),
         ValidationFailure(node: .extensionDecl, message: "child 'extendedType' should not end with 'Type'"),
         ValidationFailure(node: .genericParameter, message: "child 'inheritedType' should not end with 'Type'"),
         ValidationFailure(node: .implicitlyUnwrappedOptionalType, message: "child 'wrappedType' should not end with 'Type'"),
+        ValidationFailure(node: .isolatedType, message: "child 'baseType' should not end with 'Type'"),
+        ValidationFailure(node: .lifetimeDependenceType, message: "child 'baseType' should not end with 'Type'"),
+        ValidationFailure(node: .lifetimeSpecifiedType, message: "child 'baseType' should not end with 'Type'"),
         ValidationFailure(node: .memberType, message: "child 'baseType' should not end with 'Type'"),
         ValidationFailure(node: .metatypeType, message: "child 'baseType' should not end with 'Type'"),
         ValidationFailure(node: .optionalType, message: "child 'wrappedType' should not end with 'Type'"),
+        ValidationFailure(node: .resultDependsOnType, message: "child 'baseType' should not end with 'Type'"),
         ValidationFailure(node: .sameTypeRequirement, message: "child 'leftType' should not end with 'Type'"),
         ValidationFailure(node: .sameTypeRequirement, message: "child 'rightType' should not end with 'Type'"),
         // MARK: Adjective + Expr

Release Notes/511.md

@@ -60,6 +60,10 @@
 - `EditorPlaceholderDeclSyntax` and `EditorPlaceholderExprSyntax`:
   - Description: `EditorPlaceholderDeclSyntax` and `EditorPlaceholderExprSyntax` are now deprecated and placeholders are instead parsed as identifiers within a `MissingDeclSyntax` or `DeclReferenceExprSyntax`.
   - Pull request: https://github.com/apple/swift-syntax/pull/2237
+  
+- Type parameter modelling was changed
+  - Description: The previous design of having a single specifier on an `AttributedTypeSyntax` no longer sufficied because a function paramter type can have multiple specifiers, such as `borrowing _const String`. Re-design the way type specifiers are represented by introducing type nodes for every specifier kind: `ConstTypeSyntax` for `_const`, `IsolatedTypeSyntax` for `isolated`, `LifetimeDependenceParameterSyntax` for `_copy(parameterName)` etc., `LifetimeDependenceTypeSyntax` for `inout`, `__shared` etc., and `ResultDependsOnTypeSyntax` for `_resultDependsOn`.
+  - Pull request: https://github.com/apple/swift-syntax/pull/2433
 
 ## API-Incompatible Changes
 

Sources/SwiftParser/Parameters.swift

@@ -259,13 +259,10 @@ extension Parser {
   }
 
   mutating func parseMisplacedSpecifiers() -> [RawTokenSyntax] {
-    var misplacedSpecifiers: [RawTokenSyntax] = []
     if self.withLookahead({ !$0.startsParameterName(isClosure: false, allowMisplacedSpecifierRecovery: false) }) {
-      while canHaveParameterSpecifier, let specifier = self.consume(ifAnyIn: TypeSpecifier.self) {
-        misplacedSpecifiers.append(specifier)
-      }
+      return consumeMisplacedParameterSpecifiers()
     }
-    return misplacedSpecifiers
+    return []
   }
 }