040000 tree 78dc963a516d5629855f1cb30591f1c10402ba55	cons
100644 blob 41a5eb9ed72be60cb9ddb47f784a8be7c5b8c79f	in_place.cc
100644 blob 1ff3f591e638655dbdf9fa29702f8fa767cd4bd3	make_optional.cc
100644 blob 80927ed5ee534288a181d4e84ce0db33287e1935	nullopt.cc
040000 tree 6e9e7c24e25d36a53269c731c117b6910bfba9b8	observers
040000 tree 0cf5c6962de0321cdafe2b72d894817a0e1ffe09	relops