trait selection errors should poison the typeck results, too, so that const eval can avoid running at all

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -273,6 +273,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         error: &SelectionError<'tcx>,
         fallback_has_occurred: bool,
     ) {
+        self.set_tainted_by_errors();
         let tcx = self.tcx;
         let mut span = obligation.cause.span;