Refactor #1225: extract AttributeNameMatches helper, remove duplicate logic

https://claude.ai/code/session_01AkwUvu3XuCdj3D4axoX4UX

Author: claude

CodeConverter/CSharp/CommonConversions.cs

@@ -664,34 +664,29 @@ public bool HasOutAttribute(VBSyntax.AttributeListSyntax a)
 
     public bool IsExtensionAttribute(VBSyntax.AttributeSyntax a)
     {
-        // Guard against attributes from a different syntax tree (see IsOutAttribute for details).
-        if (a.SyntaxTree != SemanticModel.SyntaxTree) {
-            var name = a.Name.ToString();
-            return name.Equals("Extension", StringComparison.Ordinal) ||
-                   name.Equals("ExtensionAttribute", StringComparison.Ordinal) ||
-                   name.EndsWith(".Extension", StringComparison.Ordinal) ||
-                   name.EndsWith(".ExtensionAttribute", StringComparison.Ordinal);
-        }
+        if (a.SyntaxTree != SemanticModel.SyntaxTree)
+            return AttributeNameMatches(a, "Extension");
         return (SemanticModel.GetTypeInfo(a).ConvertedType?.GetFullMetadataName())
             ?.Equals(ExtensionAttributeType.FullName, StringComparison.Ordinal) == true;
     }
 
     public bool IsOutAttribute(VBSyntax.AttributeSyntax a)
     {
-        // If the attribute's syntax tree differs from the current semantic model's tree (e.g. the
-        // parameter is declared in another source file or in a metadata assembly), calling
-        // SemanticModel.GetTypeInfo on it throws "Knoten ist nicht innerhalb Syntaxbaum" /
-        // "Node is not within syntax tree". Fall back to a name-based check in that case.
-        if (a.SyntaxTree != SemanticModel.SyntaxTree) {
-            var name = a.Name.ToString();
-            return name.Equals("Out", StringComparison.Ordinal) ||
-                   name.Equals("OutAttribute", StringComparison.Ordinal) ||
-                   name.EndsWith(".Out", StringComparison.Ordinal) ||
-                   name.EndsWith(".OutAttribute", StringComparison.Ordinal);
-        }
+        if (a.SyntaxTree != SemanticModel.SyntaxTree)
+            return AttributeNameMatches(a, "Out");
         return SemanticModel.GetTypeInfo(a).ConvertedType.IsOutAttribute();
     }
 
+    // SemanticModel.GetTypeInfo throws when the node is not in its syntax tree; fall back to name matching.
+    private static bool AttributeNameMatches(VBSyntax.AttributeSyntax a, string shortName)
+    {
+        var name = a.Name.ToString();
+        return name.Equals(shortName, StringComparison.Ordinal) ||
+               name.Equals(shortName + "Attribute", StringComparison.Ordinal) ||
+               name.EndsWith("." + shortName, StringComparison.Ordinal) ||
+               name.EndsWith("." + shortName + "Attribute", StringComparison.Ordinal);
+    }
+
     public ISymbol GetCsOriginalSymbolOrNull(ISymbol symbol)
     {
         if (symbol == null) return null;