Found the following significant warnings:
  ./../inst/include/nlohmann/json_cran.h:25253:35: warning: identifier '_json' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
  ./../inst/include/nlohmann/json_cran.h:25272:49: warning: identifier '_json_pointer' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
  ../inst/include/nlohmann/json_cran.h:25253:35: warning: identifier '_json' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
  ../inst/include/nlohmann/json_cran.h:25272:49: warning: identifier '_json_pointer' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
See ‘/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/jsonStrings.Rcheck/00install.out’ for details.
* used C++ compiler: ‘Debian clang version 19.1.7 (1+b1)’
Found the following significant warnings:
  ./../inst/include/nlohmann/json_cran.h:25253:35: warning: identifier '_json' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
  ./../inst/include/nlohmann/json_cran.h:25272:49: warning: identifier '_json_pointer' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
  ../inst/include/nlohmann/json_cran.h:25253:35: warning: identifier '_json' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
  ../inst/include/nlohmann/json_cran.h:25272:49: warning: identifier '_json_pointer' preceded by whitespace in a literal operator declaration is deprecated [-Wdeprecated-literal-operator]
See ‘/data/gannet/ripley/R/packages/tests-clang/jsonStrings.Rcheck/00install.out’ for details.
* used C++ compiler: ‘clang version 20.1.0’
installed size is  5.7Mb
  sub-directories of 1Mb or more:
    libs   4.7Mb
installed size is  5.7Mb
  sub-directories of 1Mb or more:
    libs   4.7Mb
installed size is  6.0Mb
  sub-directories of 1Mb or more:
    libs   5.0Mb
installed size is  5.7Mb
  sub-directories of 1Mb or more:
    libs   4.7Mb