/// Trait implemented by error types. This should not be implemented manually. Instead, use
/// `#[derive(Diagnostic)]` -- see [rustc_macros::Diagnostic].
-#[cfg_attr(bootstrap, rustc_diagnostic_item = "SessionDiagnostic")]
-#[cfg_attr(not(bootstrap), rustc_diagnostic_item = "IntoDiagnostic")]
+#[rustc_diagnostic_item = "IntoDiagnostic"]
pub trait IntoDiagnostic<'a, T: EmissionGuarantee = ErrorGuaranteed> {
/// Write out as a diagnostic out of `Handler`.
#[must_use]