+// HACK(eddyb) maybe move this in a more central location.
+#[derive(Copy, Clone)]
+pub struct Highlighted<'tcx, T> {
+ tcx: TyCtxt<'tcx>,
+ highlight: RegionHighlightMode<'tcx>,
+ value: T,
+}
+
+impl<'tcx, T> IntoDiagnosticArg for Highlighted<'tcx, T>
+where
+ T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>, Error = fmt::Error, Output = FmtPrinter<'a, 'tcx>>,
+{
+ fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+ rustc_errors::DiagnosticArgValue::Str(self.to_string().into())
+ }
+}
+
+impl<'tcx, T> Highlighted<'tcx, T> {
+ fn map<U>(self, f: impl FnOnce(T) -> U) -> Highlighted<'tcx, U> {
+ Highlighted { tcx: self.tcx, highlight: self.highlight, value: f(self.value) }
+ }
+}
+
+impl<'tcx, T> fmt::Display for Highlighted<'tcx, T>
+where
+ T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>, Error = fmt::Error, Output = FmtPrinter<'a, 'tcx>>,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ let mut printer = ty::print::FmtPrinter::new(self.tcx, Namespace::TypeNS);
+ printer.region_highlight_mode = self.highlight;
+
+ let s = self.value.print(printer)?.into_buffer();
+ f.write_str(&s)
+ }
+}
+