Merge pull request swiftlang#1733 from kimdv/kimdv/fix-parsing-of-attribute-labels

Fix parsing `=` instead of `:`

Author: kimdv

Sources/SwiftParser/Attributes.swift

@@ -1065,12 +1065,21 @@ extension Parser {
   mutating func parseUnavailableFromAsyncArguments() -> RawUnavailableFromAsyncArgumentsSyntax {
     let (unexpectedBeforeLabel, label) = self.expect(.keyword(.message))
     let (unexpectedBeforeColon, colon) = self.expect(.colon)
+
+    let unexpectedBetweenColonAndMessage: RawUnexpectedNodesSyntax?
+    if let equalToken = self.consume(if: .equal) {
+      unexpectedBetweenColonAndMessage = RawUnexpectedNodesSyntax([equalToken], arena: self.arena)
+    } else {
+      unexpectedBetweenColonAndMessage = nil
+    }
+
     let message = self.parseStringLiteral()
     return RawUnavailableFromAsyncArgumentsSyntax(
       unexpectedBeforeLabel,
       messageLabel: label,
       unexpectedBeforeColon,
       colon: colon,
+      unexpectedBetweenColonAndMessage,
       message: message,
       arena: self.arena
     )

Sources/SwiftParser/TokenPrecedence.swift

@@ -27,6 +27,8 @@ enum TokenPrecedence: Comparable {
   case weakBracketed(closingDelimiter: RawTokenKind)
   /// A punctuator that can occur inside a statement
   case weakPunctuator
+  /// A punctuator that is a fairly strong indicator of separating two distinct parts of a statement.
+  case mediumPunctuator
   /// The closing delimiter of `weakBracketed`
   case weakBracketClose
   /// Keywords that start a new statement.
@@ -71,22 +73,24 @@ enum TokenPrecedence: Comparable {
         return 3
       case .weakPunctuator:
         return 4
-      case .weakBracketClose:
+      case .mediumPunctuator:
         return 5
-      case .stmtKeyword:
+      case .weakBracketClose:
         return 6
-      case .strongPunctuator:
+      case .stmtKeyword:
         return 7
-      case .openingBrace:
+      case .strongPunctuator:
         return 8
-      case .closingBrace:
+      case .openingBrace:
         return 9
-      case .declKeyword:
+      case .closingBrace:
         return 10
-      case .openingPoundIf:
+      case .declKeyword:
         return 11
-      case .closingPoundIf:
+      case .openingPoundIf:
         return 12
+      case .closingPoundIf:
+        return 13
       }
     }
 
@@ -143,9 +147,12 @@ enum TokenPrecedence: Comparable {
     case  // Chaining punctuators
     .infixQuestionMark, .period, .postfixQuestionMark, .exclamationMark,
       // Misc
-      .atSign, .backslash, .backtick, .colon, .comma, .ellipsis, .equal, .prefixAmpersand:
+      .backslash, .backtick, .ellipsis, .equal, .prefixAmpersand:
       self = .weakPunctuator
 
+    case .atSign, .colon, .comma:
+      self = .mediumPunctuator
+
     // MARK: Weak bracket close
     case  // Weak brackets
     .rightAngle, .rightParen, .rightSquare:

Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift

@@ -1625,6 +1625,26 @@ public class ParseDiagnosticsGenerator: SyntaxAnyVisitor {
       return .skipChildren
     }
 
+    if let equalToken = node.unexpectedBetweenColonAndMessage?.onlyPresentToken(where: { $0.tokenKind == .equal }) {
+      addDiagnostic(
+        equalToken,
+        MissingNodesError(missingNodes: [Syntax(node.colon)]),
+        fixIts: [
+          FixIt(
+            message: ReplaceTokensFixIt(
+              replaceTokens: [equalToken],
+              replacements: [node.colon]
+            ),
+            changes: [
+              FixIt.MultiNodeChange.makeMissing(equalToken),
+              FixIt.MultiNodeChange.makePresent(node.colon),
+            ]
+          )
+        ],
+        handledNodes: [equalToken.id, node.colon.id]
+      )
+    }
+
     if let token = node.unexpectedBetweenMessageLabelAndColon?.onlyPresentToken(where: { $0.tokenKind.isIdentifier }),
       token.isPresent,
       node.messageLabel.isMissing

Tests/SwiftParserTest/AttributeTests.swift

@@ -536,11 +536,10 @@ final class AttributeTests: XCTestCase {
       func foo() {}
       """,
       diagnostics: [
-        DiagnosticSpec(message: "expected ':' and string literal in @_unavailableFromAsync argument", fixIts: ["insert ':' and string literal"]),
-        DiagnosticSpec(message: #"unexpected code '= "abc"' in attribute"#),
+        DiagnosticSpec(message: "expected ':' in @_unavailableFromAsync argument", fixIts: ["replace '=' with ':'"])
       ],
       fixedSource: """
-        @_unavailableFromAsync(message: ""= "abc")
+        @_unavailableFromAsync(message: "abc")
         func foo() {}
         """
     )