MSVC (Win32) rejected the implicit conversion of the unsigned long long product to the 32-bit std::size_t (C4244 as an error). Also note when JSON_NO_THREAD_LOCAL is set in the regression test. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01N5NasAgbDGG28MqXjQvLqp Signed-off-by: Claude <noreply@anthropic.com>