These are currently recognized by the parser but are not validated semantically and are discarded somewhere along the processing chain.
We need to add the necessary hooks so these clauses are validated and interested AstProcessors can optionally propagate them into the final parsing result.
Adding support for grouping and aggregation into the existing LuceneProcessingChain/LuceneQueryParsingResult is out of scope but should be possible to add it in future.
Integrated in master.
Backported to 1.0.x branch and releasing 1.0.2.Final.