AK: Add support for "debug only" formatters

These are formatters that can only be used with debug print
functions, such as dbgln(). Currently this is limited to
Formatter<ErrorOr<T>>. With this you can still debug log ErrorOr
values (good for debugging), but trying to use them in any
String::formatted() call will fail (which prevents .to_string()
errors with the new failable strings being ignored).

You make a formatter debug only by adding a constexpr method like:
static constexpr bool is_debug_only() { return true; }

1 files changed, 1 insertions, 1 deletions

diff --git a/AK/DeprecatedString.h b/AK/DeprecatedString.h
index f9e09ae0f1..a77130161e 100644
--- a/AK/DeprecatedString.h
+++ b/AK/DeprecatedString.h
@@ -284,7 +284,7 @@ public:
     template<typename... Parameters>
     [[nodiscard]] static DeprecatedString formatted(CheckedFormatString<Parameters...>&& fmtstr, Parameters const&... parameters)
     {
-        VariadicFormatParams variadic_format_parameters { parameters... };
+        VariadicFormatParams<AllowDebugOnlyFormatters::No, Parameters...> variadic_format_parameters { parameters... };
         return vformatted(fmtstr.view(), variadic_format_parameters);
     }