message: quench a warning on Clang
diff: @@ -298,6 +298,7 @@ struct StaticArrayImpl<
  // Don't be so noisy about sign conversion in constructor
  # pragma GCC diagnostic push
  # pragma GCC diagnostic ignored "-Wsign-conversion"
  +# pragma GCC diagnostic ignored "-Wdouble-promotion"
  # pragma GCC diagnostic ignored "-Wunused-value"
  #endif
  