Found the following significant warnings:
  /usr/local/clang/include/google/protobuf/io/coded_stream.h:695:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/arenastring.h:246:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/arenastring.h:248:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/repeated_ptr_field.h:281:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/repeated_ptr_field.h:295:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/repeated_ptr_field.h:667:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/repeated_ptr_field.h:738:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/inlined_string_field.h:205:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/inlined_string_field.h:207:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:128:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:139:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:148:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:154:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:162:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:171:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:176:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:181:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:184:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:365:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:408:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:411:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:431:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:527:1: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:661:1: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:790:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:795:1: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:841:1: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:862:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:864:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:866:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:868:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:870:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:872:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:874:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:878:1: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:894:1: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:908:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:910:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:912:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:914:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:916:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:918:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:920:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:924:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/parse_context.h:929:17: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/extension_set.h:292:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/extension_set.h:297:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/extension_set.h:367:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/extension_set.h:587:5: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  /usr/local/clang/include/google/protobuf/extension_set.h:1381:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/feature_extractor.pb.h:199:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/feature_extractor.pb.h:217:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/feature_extractor.pb.h:405:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/feature_extractor.pb.h:423:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:208:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:226:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:244:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:466:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:484:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:654:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:672:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:690:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:708:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:726:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:892:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:910:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:1118:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/task_spec.pb.h:1136:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:236:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:254:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:351:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:632:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:650:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:668:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:686:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  ./cld_3/protos/sentence.pb.h:835:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/feature_extractor.pb.h:199:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/feature_extractor.pb.h:217:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/feature_extractor.pb.h:405:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/feature_extractor.pb.h:423:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:236:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:254:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:351:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:632:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:650:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:668:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:686:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/sentence.pb.h:835:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:208:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:226:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:244:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:466:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:484:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:654:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:672:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:690:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:708:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:726:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:892:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:910:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:1118:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
  cld_3/protos/task_spec.pb.h:1136:3: warning: use of the 'nodiscard' attribute is a C++17 extension [-Wc++17-attribute-extensions]
See ‘/data/gannet/ripley/R/packages/tests-clang/cld3.Rcheck/00install.out’ for details.