check array type of repeat exprs is wf

compiler/rustc_borrowck/src/renumber.rs

@@ -108,6 +108,14 @@ impl<'a, 'tcx> MutVisitor<'tcx> for RegionRenumberer<'a, 'tcx> {
         debug!(?region);
     }
 
+    #[instrument(skip(self), level = "debug")]
+    fn visit_ty_const(&mut self, ct: &mut ty::Const<'tcx>, location: Location) {
+        let old_ct = *ct;
+        *ct = self.renumber_regions(old_ct, || RegionCtxt::Location(location));
+
+        debug!(?ct);
+    }
+
     #[instrument(skip(self), level = "debug")]
     fn visit_constant(&mut self, constant: &mut Constant<'tcx>, location: Location) {
         let literal = constant.literal;

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1803,6 +1803,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             Rvalue::Repeat(operand, len) => {
                 self.check_operand(operand, location);
 
+                let array_ty = rvalue.ty(body.local_decls(), tcx);
+                self.prove_predicate(
+                    ty::PredicateKind::WellFormed(array_ty.into()),
+                    Locations::Single(location),
+                    ConstraintCategory::Boring,
+                );
+
                 // If the length cannot be evaluated we must assume that the length can be larger
                 // than 1.
                 // If the length is larger than 1, the repeat expression will need to copy the