Update src/MongoDB.Driver/Linq/Linq3Implementation/SerializerFinders/SerializerFinderVisitMember.cs

sanych-sun · Copilot · sanych-sun · commit cff7e7102fa1 · 2026-04-08T18:03:56.000-07:00
Co-authored-by: Copilot &lt;175728472+Copilot@users.noreply.github.com&gt;
diff --git a/src/MongoDB.Driver/Linq/Linq3Implementation/SerializerFinders/SerializerFinderVisitMember.cs b/src/MongoDB.Driver/Linq/Linq3Implementation/SerializerFinders/SerializerFinderVisitMember.cs
@@ -46,7 +46,7 @@ protected override Expression VisitMember(MemberExpression node)
 
                 var resultSerializer = node.Member switch
                 {
-                    _ when declaringType == typeof(BsonDocument) && !node.Member.IsIndexer() => UnknowableSerializer.Create(node.Type), // we do not support translation of BsonDocument properties other than indexer
+                    _ when typeof(BsonDocument).IsAssignableFrom(declaringType) && !node.Member.IsIndexer() => UnknowableSerializer.Create(node.Type), // we do not support translation of BsonDocument properties other than indexer
                     _ when declaringType == typeof(BsonValue) => GetBsonValuePropertySerializer(),
                     _ when IsCollectionCountOrLengthProperty() => GetCollectionCountOrLengthPropertySerializer(),
                     _ when declaringType == typeof(DateTime) => GetDateTimePropertySerializer(),

Original file line number	Diff line number	Diff line change
`@@ -46,7 +46,7 @@ protected override Expression VisitMember(MemberExpression node)`
`46`	`46`
`47`	`47`	`var resultSerializer = node.Member switch`
`48`	`48`	`{`
`49`		`- _ when declaringType == typeof(BsonDocument) && !node.Member.IsIndexer() => UnknowableSerializer.Create(node.Type), // we do not support translation of BsonDocument properties other than indexer`
	`49`	`+ _ when typeof(BsonDocument).IsAssignableFrom(declaringType) && !node.Member.IsIndexer() => UnknowableSerializer.Create(node.Type), // we do not support translation of BsonDocument properties other than indexer`
`50`	`50`	`_ when declaringType == typeof(BsonValue) => GetBsonValuePropertySerializer(),`
`51`	`51`	`_ when IsCollectionCountOrLengthProperty() => GetCollectionCountOrLengthPropertySerializer(),`
`52`	`52`	`_ when declaringType == typeof(DateTime) => GetDateTimePropertySerializer(),`