Any concrete `ImmutableRangeSet<T>` type fails to deserialize out of the box using the `GuavaDeserializers`. Only when explicitly setting `@JsonDeserialize(using = RangeSetDeserializer.class)` on the field does it work correctly. Problem seems to be in the [GuavaDeserializers.java](https://github.com/FasterXML/jackson-datatypes-collections/blob/2.16/guava/src/main/java/com/fasterxml/jackson/datatype/guava/GuavaDeserializers.java#L320-L322). This should check for `RangeSet.class.isAssignableFrom(type.getRawClass())` instead :crossed_fingers: