A Grab Bag of Miscellaneous Parser Fixes

Sources/SwiftParser/Attributes.swift

@@ -53,6 +53,10 @@ extension Parser {
       return RawSyntax(self.parseDynamicReplacementAttribute())
     case ._spi:
       return RawSyntax(self.parseSPIAttribute())
+    case ._implements:
+      return RawSyntax(self.parseImplementsAttribute())
+    case ._semantics:
+      return RawSyntax(self.parseSemanticsAttribute())
     default:
       break
     }
@@ -682,6 +686,43 @@ extension Parser {
   }
 }
 
+extension Parser {
+  mutating func parseImplementsAttribute() -> RawAttributeSyntax {
+    let (unexpectedBeforeAtSign, atSign) = self.expect(.atSign)
+    let (unexpectedBeforeSpiToken, spiToken) = self.expectContextualKeyword("_implements")
+    let (unexpectedBeforeLeftParen, leftParen) = self.expect(.leftParen)
+    let label = self.parseImplementsAttributeArguments()
+    let (unexpectedBeforeRightParen, rightParen) = self.expect(.rightParen)
+    return RawAttributeSyntax(
+      unexpectedBeforeAtSign,
+      atSignToken: atSign,
+      unexpectedBeforeSpiToken,
+      attributeName: spiToken,
+      unexpectedBeforeLeftParen,
+      leftParen: leftParen,
+      argument: RawSyntax(label),
+      unexpectedBeforeRightParen,
+      rightParen: rightParen,
+      tokenList: nil,
+      arena: self.arena)
+  }
+
+  mutating func parseImplementsAttributeArguments() -> RawImplementsAttributeArgumentsSyntax {
+    let type = self.parseTypeIdentifier()
+    let (unexpectedBeforeComma, comma) = self.expect(.comma)
+    let (name, args) = self.parseDeclNameRef([
+      .zeroArgCompoundNames,
+      .operators,
+    ])
+    return RawImplementsAttributeArgumentsSyntax(
+      type: type,
+      unexpectedBeforeComma, comma: comma,
+      declBaseName: name,
+      declNameArguments: args,
+      arena: self.arena)
+  }
+}
+
 extension Parser {
   mutating func parseOpaqueReturnTypeOfAttributeArguments() -> RawOpaqueReturnTypeOfAttributeArgumentsSyntax {
     let (unexpectedBeforeString, mangledName) = self.expect(.stringLiteral)
@@ -698,6 +739,28 @@ extension Parser {
   }
 }
 
+extension Parser {
+  mutating func parseSemanticsAttribute() -> RawAttributeSyntax {
+    let (unexpectedBeforeAtSign, atSign) = self.expect(.atSign)
+    let (unexpectedBeforeSemanticsToken, semanticsToken) = self.expectContextualKeyword("_semantics")
+    let (unexpectedBeforeLeftParen, leftParen) = self.expect(.leftParen)
+    let label = self.parseStringLiteral()
+    let (unexpectedBeforeRightParen, rightParen) = self.expect(.rightParen)
+    return RawAttributeSyntax(
+      unexpectedBeforeAtSign,
+      atSignToken: atSign,
+      unexpectedBeforeSemanticsToken,
+      attributeName: semanticsToken,
+      unexpectedBeforeLeftParen,
+      leftParen: leftParen,
+      argument: RawSyntax(label),
+      unexpectedBeforeRightParen,
+      rightParen: rightParen,
+      tokenList: nil,
+      arena: self.arena)
+  }
+}
+
 // MARK: Lookahead
 
 extension Parser.Lookahead {

Sources/SwiftParser/Declarations.swift

@@ -1232,6 +1232,17 @@ 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 firstName: RawTokenSyntax?
         let secondName: RawTokenSyntax?
         let unexpectedBeforeColon: RawUnexpectedNodesSyntax?
@@ -1291,6 +1302,9 @@ extension Parser {
         keepGoing = trailingComma != nil
         elements.append(RawFunctionParameterSyntax(
           attributes: attrs,
+          unexpectedBeforeIsolated,
+          isolated: isolated,
+          const: const,
           firstName: firstName,
           secondName: secondName,
           unexpectedBeforeColon,
@@ -1398,7 +1412,14 @@ extension Parser {
   public mutating func parseFunctionSignature() -> RawFunctionSignatureSyntax {
     let input = self.parseParameterClause(for: .functionParameters)
 
-    let async = self.consumeIfContextualKeyword("async")
+    let async: RawTokenSyntax?
+    if let asyncTok = self.consumeIfContextualKeyword("async") {
+      async = asyncTok
+    } else if let reasync = self.consumeIfContextualKeyword("reasync") {
+      async = reasync
+    } else {
+      async = nil
+    }
 
     var throwsKeyword = self.consume(ifAny: [.throwsKeyword, .rethrowsKeyword])
 

Sources/SwiftParser/Expressions.swift

@@ -317,10 +317,11 @@ extension Parser {
       }
     }
 
-    switch self.at(anyIn: AwaitTry.self) {
+    switch self.at(anyIn: AwaitTryMove.self) {
     case (.awaitContextualKeyword, let handle)?:
       let awaitTok = self.eat(handle)
-      let sub = self.parseSequenceExpressionElement(flavor, inVarOrLet: inVarOrLet)
+      let sub = self.parseSequenceExpressionElement(
+        flavor, forDirective: forDirective, inVarOrLet: inVarOrLet)
       return RawExprSyntax(RawAwaitExprSyntax(
         awaitKeyword: awaitTok,
         expression: sub,
@@ -330,13 +331,22 @@ extension Parser {
       let tryKeyword = self.eat(handle)
       let mark = self.consume(ifAny: [.exclamationMark, .postfixQuestionMark])
 
-      let expression = self.parseSequenceExpressionElement(flavor, inVarOrLet: inVarOrLet)
+      let expression = self.parseSequenceExpressionElement(
+        flavor, forDirective: forDirective, inVarOrLet: inVarOrLet)
       return RawExprSyntax(RawTryExprSyntax(
         tryKeyword: tryKeyword,
         questionOrExclamationMark: mark,
         expression: expression,
         arena: self.arena
       ))
+    case (._moveContextualKeyword, let handle)?:
+      let moveTok = self.eat(handle)
+      let sub = self.parseSequenceExpressionElement(
+        flavor, forDirective: forDirective, inVarOrLet: inVarOrLet)
+      return RawExprSyntax(RawMoveExprSyntax(
+        moveKeyword: moveTok,
+        expression: sub,
+        arena: self.arena))
     case nil:
       return self.parseUnaryExpression(flavor, forDirective: forDirective, inVarOrLet: inVarOrLet)
     }
@@ -383,7 +393,9 @@ extension Parser {
 
     default:
       // If the next token is not an operator, just parse this as expr-postfix.
-      return self.parsePostfixExpression(flavor, forDirective: forDirective, inVarOrLet: inVarOrLet)
+      return self.parsePostfixExpression(
+        flavor, forDirective: forDirective, inVarOrLet: inVarOrLet,
+        periodHasKeyPathBehavior: false)
     }
   }
 
@@ -405,26 +417,21 @@ extension Parser {
   public mutating func parsePostfixExpression(
     _ flavor: ExprFlavor,
     forDirective: Bool,
-    inVarOrLet: Bool
+    inVarOrLet: Bool,
+    periodHasKeyPathBehavior: Bool
   ) -> RawExprSyntax {
     let head = self.parsePrimaryExpression(inVarOrLet: inVarOrLet)
     guard !head.is(RawMissingExprSyntax.self) else {
       return head
     }
-    return self.parsePostfixExpressionSuffix(head, flavor, forDirective: forDirective)
+    return self.parsePostfixExpressionSuffix(
+      head, flavor, forDirective: forDirective,
+      periodHasKeyPathBehavior: periodHasKeyPathBehavior)
   }
 
   @_spi(RawSyntax)
   public mutating func parseDottedExpressionSuffix(_ start: RawExprSyntax?) -> RawExprSyntax {
     assert(self.at(any: [.period, .prefixPeriod]))
-
-      // A key path is special, because it allows .[, unlike anywhere else. The
-      // period itself should be left in the token stream. (.? and .! end up
-      // being operators, and so aren't handled here.)
-//        if (periodHasKeyPathBehavior && peekToken().is(tok::l_square)) {
-//          break
-//        }
-
     let period = self.consumeAnyToken(remapping: .period)
     // Handle "x.42" - a tuple index.
     if let name = self.consume(if: .integerLiteral) {
@@ -478,7 +485,9 @@ extension Parser {
         // TODO: diagnose and skip.
         return nil
       }
-      let result = parser.parsePostfixExpressionSuffix(head, flavor, forDirective: forDirective)
+      let result = parser.parsePostfixExpressionSuffix(
+        head, flavor, forDirective: forDirective,
+        periodHasKeyPathBehavior: false)
 
       // TODO: diagnose and skip the remaining token in the current clause.
       return result
@@ -513,7 +522,8 @@ extension Parser {
   public mutating func parsePostfixExpressionSuffix(
     _ start: RawExprSyntax,
     _ flavor: ExprFlavor,
-    forDirective: Bool
+    forDirective: Bool,
+    periodHasKeyPathBehavior: Bool
   ) -> RawExprSyntax {
     // Handle suffix expressions.
     var leadingExpr = start
@@ -525,6 +535,13 @@ extension Parser {
 
       // Check for a .foo suffix.
       if self.at(any: [.period, .prefixPeriod]) {
+        // A key path is special, because it allows .[, unlike anywhere else. The
+        // period itself should be left in the token stream. (.? and .! end up
+        // being operators, and so aren't handled here.)
+        if periodHasKeyPathBehavior && self.peek().tokenKind == .leftSquareBracket {
+          break
+        }
+
         leadingExpr = self.parseDottedExpressionSuffix(leadingExpr)
         continue
       }
@@ -700,7 +717,9 @@ extension Parser {
     // the token is a operator starts with '.', or the following token is '['.
     let root: RawExprSyntax?
     if !self.currentToken.starts(with: ".") {
-      root = self.parsePostfixExpression(.basic, forDirective: forDirective, inVarOrLet: inVarOrLet)
+      root = self.parsePostfixExpression(
+        .basic, forDirective: forDirective, inVarOrLet: inVarOrLet,
+        periodHasKeyPathBehavior: true)
     } else {
       root = nil
     }
@@ -714,12 +733,16 @@ extension Parser {
         dot = self.consumeAnyToken()
       }
       let base = RawExprSyntax(RawKeyPathBaseExprSyntax(period: dot, arena: self.arena))
-      expression = self.parsePostfixExpressionSuffix(base, .basic, forDirective: forDirective)
+      expression = self.parsePostfixExpressionSuffix(
+        base, .basic, forDirective: forDirective,
+        periodHasKeyPathBehavior: false)
     } else if self.at(any: [.period, .prefixPeriod]) {
       // Inside a keypath's path, the period always behaves normally: the key path
       // behavior is only the separation between type and path.
       let base = self.parseDottedExpressionSuffix(nil)
-      expression = self.parsePostfixExpressionSuffix(base, .basic, forDirective: forDirective)
+      expression = self.parsePostfixExpressionSuffix(
+        base, .basic, forDirective: forDirective,
+        periodHasKeyPathBehavior: false)
     } else {
       expression = RawExprSyntax(RawMissingExprSyntax(arena: self.arena))
     }
@@ -870,7 +893,7 @@ extension Parser {
       // 'any' followed by another identifier is an existential type.
       if self.atContextualKeyword("any"),
          self.peek().tokenKind == .identifier,
-         self.peek().isAtStartOfLine
+         !self.peek().isAtStartOfLine
       {
         let ty = self.parseType()
         return RawExprSyntax(RawTypeExprSyntax(type: ty, arena: self.arena))

Sources/SwiftParser/Modifiers.swift

@@ -24,6 +24,8 @@ extension Parser {
           (.internalKeyword, _)?,
           (.publicKeyword, _)?:
         elements.append(parseAccessLevelModifier())
+      case (.open, _)?:
+        elements.append(parseOpenAccessLevelModifier())
       case (.staticKeyword, let handle)?:
         let staticKeyword = self.eat(handle)
         elements.append(RawDeclModifierSyntax(
@@ -64,7 +66,6 @@ extension Parser {
         (.nonmutating, _)?,
         (.convenience, _)?,
         (.override, _)?,
-        (.open, _)?,
         (.weak, _)?,
         (.indirect, _)?,
         (.isolated, _)?,
@@ -130,43 +131,54 @@ extension Parser {
     )
   }
 
+  mutating func parseOpenAccessLevelModifier() -> RawDeclModifierSyntax {
+    let (unexpectedBeforeName, name) = self.expectContextualKeyword("open")
+    let details = self.parseAccessModifierDetails()
+    return RawDeclModifierSyntax(
+      unexpectedBeforeName,
+      name: name,
+      detail: details,
+      arena: self.arena)
+  }
+
   mutating func parseAccessLevelModifier() -> RawDeclModifierSyntax {
     let (unexpectedBeforeName, name) = expectAny(
       [.privateKeyword, .fileprivateKeyword, .internalKeyword, .publicKeyword],
       default: .internalKeyword
     )
-    let details: RawDeclModifierDetailSyntax?
-    if let leftParen = consume(if: .leftParen) {
-      let unexpectedBeforeDetail: RawUnexpectedNodesSyntax?
-      let detail: RawTokenSyntax
-      if let setHandle = canRecoverToContextualKeyword("set", precedence: .weakBracketClose) {
-        (unexpectedBeforeDetail, detail) = eat(setHandle)
-      } else {
-        unexpectedBeforeDetail = nil
-        detail = RawTokenSyntax(
-          missing: .contextualKeyword,
-          text: "set",
-          arena: arena
-        )
-      }
-      let (unexpectedBeforeRightParen, rightParen) = expect(.rightParen)
-
-      details = RawDeclModifierDetailSyntax(
-        leftParen: leftParen,
-        unexpectedBeforeDetail,
-        detail: detail,
-        unexpectedBeforeRightParen,
-        rightParen: rightParen,
-        arena: arena
-      )
-    } else {
-      details = nil
-    }
+    let details = self.parseAccessModifierDetails()
     return RawDeclModifierSyntax(
       unexpectedBeforeName,
       name: name,
       detail: details,
-      arena: arena
-    )
+      arena: self.arena)
+  }
+
+  mutating func parseAccessModifierDetails() -> RawDeclModifierDetailSyntax? {
+    guard let leftParen = consume(if: .leftParen) else {
+      return nil
+    }
+
+    let unexpectedBeforeDetail: RawUnexpectedNodesSyntax?
+    let detail: RawTokenSyntax
+    if let setHandle = canRecoverToContextualKeyword("set", precedence: .weakBracketClose) {
+      (unexpectedBeforeDetail, detail) = eat(setHandle)
+    } else {
+      unexpectedBeforeDetail = nil
+      detail = RawTokenSyntax(
+        missing: .contextualKeyword,
+        text: "set",
+        arena: arena
+      )
+    }
+    let (unexpectedBeforeRightParen, rightParen) = expect(.rightParen)
+
+    return RawDeclModifierDetailSyntax(
+      leftParen: leftParen,
+      unexpectedBeforeDetail,
+      detail: detail,
+      unexpectedBeforeRightParen,
+      rightParen: rightParen,
+      arena: self.arena)
   }
 }