fix wrong insert of mesage in UnavailableFromAsyncArgumentsSyntax

Author: kimdv

Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift

@@ -1376,6 +1376,36 @@ public class ParseDiagnosticsGenerator: SyntaxAnyVisitor {
     return .visitChildren
   }
 
+  public override func visit(_ node: UnavailableFromAsyncArgumentsSyntax) -> SyntaxVisitorContinueKind {
+    if shouldSkip(node) {
+      return .skipChildren
+    }
+
+    if let token = node.unexpectedBetweenMessageLabelAndColon?.onlyToken(where: { $0.tokenKind.isIdentifier }),
+      node.messageLabel.presence == .missing
+    {
+      addDiagnostic(
+        node,
+        MissingNodesError(missingNodes: [Syntax(node.messageLabel)]),
+        fixIts: [
+          FixIt(
+            message: ReplaceTokensFixIt(
+              replaceTokens: [token],
+              replacements: [node.messageLabel]
+            ),
+            changes: [
+              FixIt.MultiNodeChange.makeMissing(token),
+              FixIt.MultiNodeChange.makePresentBeforeTrivia(node.messageLabel),
+            ]
+          )
+        ],
+        handledNodes: [node.messageLabel.id, token.id]
+      )
+    }
+
+    return .visitChildren
+  }
+
   public override func visit(_ node: UnresolvedTernaryExprSyntax) -> SyntaxVisitorContinueKind {
     if shouldSkip(node) {
       return .skipChildren

Tests/SwiftParserTest/AttributeTests.swift

@@ -486,9 +486,12 @@ final class AttributeTests: XCTestCase {
       func foo() {}
       """,
       diagnostics: [
-        DiagnosticSpec(message: "expected 'message' in @_unavailableFromAsync argument", fixIts: ["insert 'message'"]),
-        DiagnosticSpec(message: "unexpected code 'nope' before @_unavailableFromAsync argument"),
-      ]
+        DiagnosticSpec(message: "expected 'message' in @_unavailableFromAsync argument", fixIts: ["insert 'message'"])
+      ],
+      fixedSource: """
+        @_unavailableFromAsync(message: "abc")
+        func foo() {}
+        """
     )
 
     assertParse(