Bring an enum's members into scope to improve readability. Before:

enum class rgba_color_channel { red, green, blue, alpha };

std::string_view to_string(rgba_color_channel channel) {
  switch (channel) {
    case rgba_color_channel::red:   return "red";
    case rgba_color_channel::green: return "green";
    case rgba_color_channel::blue:  return "blue";
    case rgba_color_channel::alpha: return "alpha";
  }
}

After:

enum class rgba_color_channel { red, green, blue, alpha };

std::string_view to_string(rgba_color_channel my_channel) {
  switch (my_channel) {
    using enum rgba_color_channel;
    case red:   return "red";
    case green: return "green";
    case blue:  return "blue";
    case alpha: return "alpha";
  }
}