Found the following significant warnings:
  ../src/s2/util/coding/coder.h:161:44: warning: 'exchange<char *, char *>' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/coding/coder.h:493:23: warning: 'is_trivially_copy_constructible' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/coding/coder.h:495:23: warning: 'is_trivially_copy_assignable' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/coding/coder.h:497:23: warning: 'is_trivially_destructible' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:62:34: warning: 'make_index_sequence' is deprecated: Use std::make_index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:70:31: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:311:53: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:317:46: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:322:47: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:327:38: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:332:38: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/gtl/compact_array.h:523:23: warning: 'is_trivially_copy_constructible' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/gtl/compact_array.h:524:23: warning: 'is_trivially_copy_assignable' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/gtl/compact_array.h:525:23: warning: 'is_trivially_destructible' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/gtl/compact_array.h:362:16: warning: 'is_trivially_default_constructible' is deprecated [-Wdeprecated-declarations]
  ../src/s2/s2cell_iterator.h:89:3: warning: 'decay_t' is deprecated [-Wdeprecated-declarations]
  70:31: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  /usr/local/clang/include/absl/strings/str_format.h../src/s2/util/math/vector.h::38070::4331::  warning: warning: type nullability specifier '_Nonnull' is a Clang extension [-Wnullability-extension]'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:317:46: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]In file included from 
  : warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  s2/mutable_s2shape_index.cc:470:38: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/mutable_s2shape_index.cc:483:36: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2lax_loop_shape.cc:38:27: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2lax_loop_shape.cc:43:25: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2lax_loop_shape.cc:95:27: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2lax_loop_shape.cc:102:25: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  47: warning: ../src/s2/s2point.h'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]:
  ../src/s2/util/math/vector.h:327:38: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]In file included from 
  ../src/s2/util/math/vector.h../src/s2/util/math/vector.h::7070::3131::  warning: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  /usr/local/clang/include/absl/utility/utility.h../src/s2/util/math/vector.h::91322::2447::  note: warning: 'index_sequence' has been explicitly marked deprecated here'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  38: warning:    'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]91
  s2/s2loop.cc:113:20: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2loop.cc:114:27: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2loop.cc:132:18: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  s2/s2loop.cc:133:25: warning: 'exchange<int, int>' is deprecated [-Wdeprecated-declarations]
  :16: warning:   'is_trivially_default_constructible' is deprecated [-Wdeprecated-declarations]860
  u/usr/local/clang/include/absl/base/nullability.h../src/s2/util/coding/coder.hl::l241161a::b2244i::l  inote: warning: texpanded from macro 'absl_nonnull''exchange<char *, char *>' is deprecated [-Wdeprecated-declarations]y
  ../src/s2/util/math/vector.h:70:31: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]In file included from 
  :62:34: warning: 'make_index_sequence' is deprecated: Use std::make_index_sequence instead. [-Wdeprecated-declarations]
  3: warning: 'decay_t' is deprecated [-Wdeprecated-declarations]/usr/local/clang/include/absl/base/nullability.h
  T../src/s2/util/math/vector.hU:R332E:D38: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  :38: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  :31: warning:   'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]241
  :31: warning:   'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]465
  : warning: 'decay_t' is deprecated [-Wdeprecated-declarations]/usr/local/clang/include/absl/base/nullability.h
  70:31: warning: ../src/s2/util/math/vector.h'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]:
  53: warning: ../src/s2/util/math/vector.h'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]:
  ../src/s2/util/math/vector.h:322:47: warning: In file included from 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]s2/s2shape_index.cc
  ../src/s2/util/gtl/compact_array.h:524:23: warning: In file included from 'is_trivially_copy_assignable' is deprecated [-Wdeprecated-declarations]s2/s2shape_index.cc
  70:31: warning:   'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]425
  ../src/s2/util/math/vector.h/usr/local/clang/include/absl/strings/cord.h::70927::3143::  warning: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]type nullability specifier '_Nullable' is a Clang extension [-Wnullability-extension]
  3: warning: 'decay_t' is deprecated [-Wdeprecated-declarations] 
  :46: warning:   'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]489
  /usr/local/clang/include/absl/base/nullability.h../src/s2/util/coding/coder.h::257161::2344::  note: warning: expanded from macro 'absl_nullable''exchange<char *, char *>' is deprecated [-Wdeprecated-declarations]
  /usr/local/clang/include/absl/base/nullability.h../src/s2/util/math/vector.h::25762::2334::  note: warning: expanded from macro 'absl_nullable''make_index_sequence' is deprecated: Use std::make_index_sequence instead. [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:: warning: 'is_trivially_copy_constructible' is deprecated [-Wdeprecated-declarations]
  ../src/s2/util/math/vector.h:311:53: warning: In file included from 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]s2/s2shapeutil_edge_iterator.cc
  ../src/s2/util/math/vector.h/usr/local/clang/include/absl/strings/numbers.h::33288::3862::  warning: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]type nullability specifier '_Nonnull' is a Clang extension [-Wnullability-extension]
  31: warning: 'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
  &../src/s2/util/math/vector.h/usr/local/clang/include/absl/log/internal/check_op.h ::S311514t::r5313A::p  pwarning: warning: e'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]type nullability specifier '_Nullable' is a Clang extension [-Wnullability-extension]n
  /usr/local/clang/include/absl/base/nullability.h../src/s2/util/math/vector.h::24162::2234::  note: warning: expanded from macro 'absl_nonnull''make_index_sequence' is deprecated: Use std::make_index_sequence instead. [-Wdeprecated-declarations]
  s2/util/coding/coder.cc:36:20: warning: 'exchange<unsigned char *, std::nullptr_t>' is deprecated [-Wdeprecated-declarations]
  s2/util/coding/coder.cc/usr/local/clang/include/absl/log/internal/check_op.h::37277::3250::  warning: warning: 'exchange<unsigned char *, std::nullptr_t>' is deprecated [-Wdeprecated-declarations]type nullability specifier '_Nullable' is a Clang extension [-Wnullability-extension]
  s2/util/coding/coder.cc:44:18: warning: 'exchange<unsigned char *, std::nullptr_t>' is deprecated [-Wdeprecated-declarations]
  s2/util/coding/coder.cc/usr/local/clang/include/absl/log/internal/check_op.h::45298::3022::  warning: warning: 'exchange<unsigned char *, std::nullptr_t>' is deprecated [-Wdeprecated-declarations]type nullability specifier '_Nonnull' is a Clang extension [-Wnullability-extension]
  ../src/s2/util/math/vector.h/usr/local/clang/include/absl/log/internal/check_op.h::62189::3428::  warning: warning: 'make_index_sequence' is deprecated: Use std::make_index_sequence instead. [-Wdeprecated-declarations]type nullability specifier '_Nonnull' is a Clang extension [-Wnullability-extension]
  : warning: 'decay_t' is deprecated [-Wdeprecated-declarations]  
  331In file included from ::../src/s2/mutable_s2shape_index.h  :note: warning: 30expanded from macro 'CHECK_NE''index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]:
  ../src/s2/s2shape_index.h:308:3: warning: 'decay_t' is deprecated [-Wdeprecated-declarations]
  ../src/s2/s2cell_range_iterator.h:122:36: warning: 'decay_t' is deprecated [-Wdeprecated-declarations]
  /usr/local/clang/include/absl/log/internal/check_op.h../src/s2/util/math/vector.h::50370::131::  warning: warning: type nullability specifier '_Nullable' is a Clang extension [-Wnullability-extension]'index_sequence' is deprecated: Use std::index_sequence instead. [-Wdeprecated-declarations]
See ‘/data/localhost/ripley/R/packages/tests-clang/s2.Rcheck/00install.out’ for details.
* used C compiler: ‘clang version 22.1.8’
* used C++ compiler: ‘clang version 22.1.8’