Merge pull request swiftlang#1986 from ahoppen/ahoppen/disallow-self-in-types

Disallow the `self`/`Self` keyword where it’s not allowed in types

Author: ahoppen

CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift

@@ -300,7 +300,7 @@ public let TYPE_NODES: [Node] = [
       ),
       Child(
         name: "name",
-        kind: .token(choices: [.token(.identifier), .keyword(.self), .keyword(.Self)]),
+        kind: .token(choices: [.token(.identifier), .keyword(.self)]),
         nameForDiagnostics: "name"
       ),
       Child(
@@ -435,7 +435,6 @@ public let TYPE_NODES: [Node] = [
         name: "name",
         kind: .token(choices: [
           .token(.identifier),
-          .keyword(.self),
           .keyword(.Self),
           .keyword(.Any),
           .token(.wildcard),

Sources/SwiftParser/Names.swift

@@ -151,7 +151,7 @@ extension Parser {
 
     if self.lookahead().canParseBaseTypeForQualifiedDeclName() {
       type = RawExprSyntax(RawTypeExprSyntax(type: self.parseQualifiedTypeIdentifier(), arena: self.arena))
-      period = self.consumePrefix(".", as: .period)
+      period = self.expectWithoutRecovery(prefix: ".", as: .period)
     } else {
       type = nil
       period = nil
@@ -181,52 +181,70 @@ extension Parser {
       return RawTypeSyntax(self.parseAnyType())
     }
 
-    var result: RawTypeSyntax?
-    var keepGoing: RawTokenSyntax? = nil
+    let (unexpectedBeforeName, name) = self.expect(anyIn: IdentifierTypeSyntax.NameOptions.self, default: .identifier)
+    let generics: RawGenericArgumentClauseSyntax?
+    if self.atContextualPunctuator("<") {
+      generics = self.parseGenericArguments()
+    } else {
+      generics = nil
+    }
+
+    var result = RawTypeSyntax(
+      RawIdentifierTypeSyntax(
+        unexpectedBeforeName,
+        name: name,
+        genericArgumentClause: generics,
+        arena: self.arena
+      )
+    )
+
+    // If qualified name base type cannot be parsed from the current
+    // point (i.e. the next type identifier is not followed by a '.'),
+    // then the next identifier is the final declaration name component.
+    var backtrack = self.lookahead()
+    guard
+      backtrack.consume(ifPrefix: ".", as: .period) != nil,
+      backtrack.canParseBaseTypeForQualifiedDeclName()
+    else {
+      return result
+    }
+
+    var keepGoing = self.consume(if: .period)
     var loopProgress = LoopProgressCondition()
-    repeat {
-      let (unexpectedBeforeName, name) = self.expect(.identifier, .keyword(.self), .keyword(.Self), default: .identifier)
+    while keepGoing != nil && self.hasProgressed(&loopProgress) {
+      let (unexpectedBeforeName, name) = self.expect(.identifier, .keyword(.self), TokenSpec(.Self, remapping: .identifier), default: .identifier)
       let generics: RawGenericArgumentClauseSyntax?
       if self.atContextualPunctuator("<") {
         generics = self.parseGenericArguments()
       } else {
         generics = nil
       }
-      if let keepGoing {
-        result = RawTypeSyntax(
-          RawMemberTypeSyntax(
-            baseType: result!,
-            period: keepGoing,
-            unexpectedBeforeName,
-            name: name,
-            genericArgumentClause: generics,
-            arena: self.arena
-          )
-        )
-      } else {
-        result = RawTypeSyntax(
-          RawIdentifierTypeSyntax(
-            unexpectedBeforeName,
-            name: name,
-            genericArgumentClause: generics,
-            arena: self.arena
-          )
+      result = RawTypeSyntax(
+        RawMemberTypeSyntax(
+          baseType: result,
+          period: keepGoing!,
+          unexpectedBeforeName,
+          name: name,
+          genericArgumentClause: generics,
+          arena: self.arena
         )
-      }
+      )
 
       // If qualified name base type cannot be parsed from the current
       // point (i.e. the next type identifier is not followed by a '.'),
       // then the next identifier is the final declaration name component.
       var backtrack = self.lookahead()
-      backtrack.consumePrefix(".", as: .period)
-      guard backtrack.canParseBaseTypeForQualifiedDeclName() else {
+      guard
+        backtrack.consume(ifPrefix: ".", as: .period) != nil,
+        backtrack.canParseBaseTypeForQualifiedDeclName()
+      else {
         break
       }
 
       keepGoing = self.consume(if: .period)
-    } while keepGoing != nil && self.hasProgressed(&loopProgress)
+    }
 
-    return result!
+    return result
   }
 }
 

Sources/SwiftParser/Parameters.swift

@@ -97,7 +97,11 @@ extension Parser {
 
     let type: RawTypeSyntax
 
-    if colon.presence == .missing, let secondName = names.secondName, secondName.tokenText.isStartingWithUppercase {
+    if colon.presence == .missing,
+      let secondName = names.secondName,
+      secondName.tokenKind == .identifier,
+      secondName.tokenText.isStartingWithUppercase
+    {
       // Synthesize the secondName parameter as a type node.
       type = RawTypeSyntax(
         RawIdentifierTypeSyntax(

Sources/SwiftParser/Parser.swift

@@ -635,6 +635,7 @@ extension Parser {
   ///     currently positioned at a keyword, consume that keyword and remap it
   ///     to and identifier.
   /// - Returns: The consumed token and any unexpected tokens that were skipped.
+  ///   The token is always guaranteed to be of `TokenKind.identifier`
   mutating func expectIdentifier(
     keywordRecovery: Bool = false,
     allowSelfOrCapitalSelfAsIdentifier: Bool = false,

Sources/SwiftParser/Types.swift

@@ -270,7 +270,20 @@ extension Parser {
             )
           )
         } else {
-          let (name, generics) = self.parseTypeNameWithGenerics(allowKeywordAsName: true)
+          let name: RawTokenSyntax
+          if let handle = self.at(anyIn: MemberTypeSyntax.NameOptions.self)?.handle {
+            name = self.eat(handle)
+          } else if self.currentToken.isLexerClassifiedKeyword {
+            name = self.consumeAnyToken(remapping: .identifier)
+          } else {
+            name = missingToken(.identifier)
+          }
+          let generics: RawGenericArgumentClauseSyntax?
+          if self.atContextualPunctuator("<") {
+            generics = self.parseGenericArguments()
+          } else {
+            generics = nil
+          }
           base = RawTypeSyntax(
             RawMemberTypeSyntax(
               baseType: base,
@@ -322,30 +335,23 @@ extension Parser {
     )
   }
 
-  mutating func parseTypeNameWithGenerics(allowKeywordAsName: Bool) -> (RawTokenSyntax, RawGenericArgumentClauseSyntax?) {
-    let name: RawTokenSyntax
-    if let identOrSelf = self.consume(if: .identifier, .keyword(.self), .keyword(.Self)) {
-      name = identOrSelf
-    } else if allowKeywordAsName && self.currentToken.isLexerClassifiedKeyword {
-      name = self.consumeAnyToken(remapping: .identifier)
-    } else {
-      name = missingToken(.identifier)
-    }
-    if self.atContextualPunctuator("<") {
-      return (name, self.parseGenericArguments())
-    }
-    return (name, nil)
-  }
-
   /// Parse a type identifier.
   mutating func parseTypeIdentifier() -> RawTypeSyntax {
     if self.at(.keyword(.Any)) {
       return RawTypeSyntax(self.parseAnyType())
     }
 
-    let (name, generics) = parseTypeNameWithGenerics(allowKeywordAsName: false)
+    let (unexpectedBeforeName, name) = self.expect(anyIn: IdentifierTypeSyntax.NameOptions.self, default: .identifier)
+    let generics: RawGenericArgumentClauseSyntax?
+    if self.atContextualPunctuator("<") {
+      generics = self.parseGenericArguments()
+    } else {
+      generics = nil
+    }
+
     return RawTypeSyntax(
       RawIdentifierTypeSyntax(
+        unexpectedBeforeName,
         name: name,
         genericArgumentClause: generics,
         arena: self.arena
@@ -479,6 +485,7 @@ extension Parser {
         if let first,
           second == nil,
           colon?.isMissing == true,
+          first.tokenKind == .identifier,
           first.tokenText.isStartingWithUppercase
         {
           elements.append(

Sources/SwiftParser/generated/Parser+TokenSpecSet.swift

@@ -1559,7 +1559,6 @@ extension IdentifierTypeSyntax {
   @_spi(Diagnostics)
   public enum NameOptions: TokenSpecSet {
     case identifier
-    case `self`
     case `Self`
     case `Any`
     case wildcard
@@ -1568,8 +1567,6 @@ extension IdentifierTypeSyntax {
       switch PrepareForKeywordMatch(lexeme) {
       case TokenSpec(.identifier):
         self = .identifier
-      case TokenSpec(.self):
-        self = .self
       case TokenSpec(.Self):
         self = .Self
       case TokenSpec(.Any):
@@ -1585,8 +1582,6 @@ extension IdentifierTypeSyntax {
       switch self {
       case .identifier:
         return .identifier
-      case .self:
-        return .keyword(.self)
       case .Self:
         return .keyword(.Self)
       case .Any:
@@ -1604,8 +1599,6 @@ extension IdentifierTypeSyntax {
       switch self {
       case .identifier:
         return .identifier("")
-      case .self:
-        return .keyword(.self)
       case .Self:
         return .keyword(.Self)
       case .Any:
@@ -2097,16 +2090,13 @@ extension MemberTypeSyntax {
   public enum NameOptions: TokenSpecSet {
     case identifier
     case `self`
-    case `Self`
 
     init?(lexeme: Lexer.Lexeme) {
       switch PrepareForKeywordMatch(lexeme) {
       case TokenSpec(.identifier):
         self = .identifier
       case TokenSpec(.self):
         self = .self
-      case TokenSpec(.Self):
-        self = .Self
       default:
         return nil
       }
@@ -2118,8 +2108,6 @@ extension MemberTypeSyntax {
         return .identifier
       case .self:
         return .keyword(.self)
-      case .Self:
-        return .keyword(.Self)
       }
     }
 
@@ -2133,8 +2121,6 @@ extension MemberTypeSyntax {
         return .identifier("")
       case .self:
         return .keyword(.self)
-      case .Self:
-        return .keyword(.Self)
       }
     }
   }

Sources/SwiftSyntax/generated/raw/RawSyntaxValidation.swift

@@ -1406,7 +1406,6 @@ func validateLayout(layout: RawSyntaxBuffer, as kind: SyntaxKind) {
     assertNoError(kind, 0, verify(layout[0], as: RawUnexpectedNodesSyntax?.self))
     assertNoError(kind, 1, verify(layout[1], as: RawTokenSyntax.self, tokenChoices: [
             .tokenKind(.identifier), 
-            .keyword("self"), 
             .keyword("Self"), 
             .keyword("Any"), 
             .tokenKind(.wildcard)
@@ -1805,7 +1804,7 @@ func validateLayout(layout: RawSyntaxBuffer, as kind: SyntaxKind) {
     assertNoError(kind, 2, verify(layout[2], as: RawUnexpectedNodesSyntax?.self))
     assertNoError(kind, 3, verify(layout[3], as: RawTokenSyntax.self, tokenChoices: [.tokenKind(.period)]))
     assertNoError(kind, 4, verify(layout[4], as: RawUnexpectedNodesSyntax?.self))
-    assertNoError(kind, 5, verify(layout[5], as: RawTokenSyntax.self, tokenChoices: [.tokenKind(.identifier), .keyword("self"), .keyword("Self")]))
+    assertNoError(kind, 5, verify(layout[5], as: RawTokenSyntax.self, tokenChoices: [.tokenKind(.identifier), .keyword("self")]))
     assertNoError(kind, 6, verify(layout[6], as: RawUnexpectedNodesSyntax?.self))
     assertNoError(kind, 7, verify(layout[7], as: RawGenericArgumentClauseSyntax?.self))
     assertNoError(kind, 8, verify(layout[8], as: RawUnexpectedNodesSyntax?.self))

Sources/SwiftSyntax/generated/syntaxNodes/SyntaxTypeNodes.swift

@@ -970,7 +970,7 @@ public struct FunctionTypeSyntax: TypeSyntaxProtocol, SyntaxHashable {
 
 /// ### Children
 /// 
-///  - `name`: (`<identifier>` | `'self'` | `'Self'` | `'Any'` | `'_'`)
+///  - `name`: (`<identifier>` | `'Self'` | `'Any'` | `'_'`)
 ///  - `genericArgumentClause`: ``GenericArgumentClauseSyntax``?
 public struct IdentifierTypeSyntax: TypeSyntaxProtocol, SyntaxHashable {
   public let _syntaxNode: Syntax
@@ -1218,7 +1218,7 @@ public struct ImplicitlyUnwrappedOptionalTypeSyntax: TypeSyntaxProtocol, SyntaxH
 /// 
 ///  - `baseType`: ``TypeSyntax``
 ///  - `period`: `'.'`
-///  - `name`: (`<identifier>` | `'self'` | `'Self'`)
+///  - `name`: (`<identifier>` | `'self'`)
 ///  - `genericArgumentClause`: ``GenericArgumentClauseSyntax``?
 public struct MemberTypeSyntax: TypeSyntaxProtocol, SyntaxHashable {
   public let _syntaxNode: Syntax

Tests/SwiftParserTest/Assertions.swift

@@ -529,35 +529,6 @@ public struct AssertParseOptions: OptionSet {
 }
 
 extension ParserTestCase {
-  /// Same as `assertParse` overload with a `(String) -> S` `parse`,
-  /// parsing the resulting `String` as a ``SourceFileSyntax``.
-  func assertParse(
-    _ markedSource: String,
-    substructure expectedSubstructure: (some SyntaxProtocol)? = Optional<Syntax>.none,
-    substructureAfterMarker: String = "START",
-    diagnostics expectedDiagnostics: [DiagnosticSpec] = [],
-    applyFixIts: [String]? = nil,
-    fixedSource expectedFixedSource: String? = nil,
-    options: AssertParseOptions = [],
-    experimentalFeatures: Parser.ExperimentalFeatures? = nil,
-    file: StaticString = #file,
-    line: UInt = #line
-  ) {
-    assertParse(
-      markedSource,
-      { SourceFileSyntax.parse(from: &$0) },
-      substructure: expectedSubstructure,
-      substructureAfterMarker: substructureAfterMarker,
-      diagnostics: expectedDiagnostics,
-      applyFixIts: applyFixIts,
-      fixedSource: expectedFixedSource,
-      options: options,
-      experimentalFeatures: experimentalFeatures,
-      file: file,
-      line: line
-    )
-  }
-
   /// After a test case has been mutated, assert that the mutated source
   /// round-trips and doesn’t hit any assertion failures in the parser.
   fileprivate func assertRoundTrip<S: SyntaxProtocol>(
@@ -615,7 +586,7 @@ extension ParserTestCase {
   ///     `nil` to enable the default set of features provided by the test case.
   func assertParse<S: SyntaxProtocol>(
     _ markedSource: String,
-    _ parse: (inout Parser) -> S,
+    _ parse: (inout Parser) -> S = { SourceFileSyntax.parse(from: &$0) },
     substructure expectedSubstructure: (some SyntaxProtocol)? = Optional<Syntax>.none,
     substructureAfterMarker: String = "START",
     diagnostics expectedDiagnostics: [DiagnosticSpec] = [],

Tests/SwiftParserTest/AttributeTests.swift

@@ -220,6 +220,24 @@ final class AttributeTests: ParserTestCase {
       ) {}
       """
     )
+
+    assertParse(
+      """
+      @derivative(of: 1️⃣Self.other)
+      func foo() {}
+      """,
+      substructure: Syntax(TokenSyntax.keyword(.Self)),
+      substructureAfterMarker: "1️⃣"
+    )
+
+    assertParse(
+      """
+      @derivative(of: Foo.1️⃣Self.other)
+      func foo() {}
+      """,
+      substructure: Syntax(TokenSyntax.identifier("Self")),
+      substructureAfterMarker: "1️⃣"
+    )
   }
 
   func testTransposeAttribute() {