+ /// Translatable message which has already been translated eagerly.
+ ///
+ /// Some diagnostics have repeated subdiagnostics where the same interpolated variables would
+ /// be instantiated multiple times with different values. As translation normally happens
+ /// immediately prior to emission, after the diagnostic and subdiagnostic derive logic has run,
+ /// the setting of diagnostic arguments in the derived code will overwrite previous variable
+ /// values and only the final value will be set when translation occurs - resulting in
+ /// incorrect diagnostics. Eager translation results in translation for a subdiagnostic
+ /// happening immediately after the subdiagnostic derive's logic has been run. This variant
+ /// stores messages which have been translated eagerly.
+ // FIXME(#100717): can a `Cow<'static, str>` be used here?
+ Eager(String),