Fabio Massimo Ercoli An easy way to implement the check in Search 6 would be to detect that the indexed embedded is applied on a type that has no mapping contributor attached, i.e. in this code in PojoIndexingProcessorValueNodeBuilderDelegate#indexedEmbedded:

			mappingHelper.getContributorProvider().forEach(
					embeddedTypeModelPath.getTypeModel().getRawType(),
					c -> c.contributeMapping( nestedProcessorBuilder )
			);

... throw an exception if the lambda is not called even once.

It'll probably be easier to replace the "forEach" method with a "get" method that returns a collection, that way you can easily test emptiness.