Type level consts can show up in MIR type checker

Author: compiler-errors

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -349,8 +349,8 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
             let tcx = self.tcx();
             let maybe_uneval = match constant.const_ {
                 Const::Ty(_, ct) => match ct.kind() {
-                    ty::ConstKind::Unevaluated(_) => {
-                        bug!("should not encounter unevaluated Const::Ty here, got {:?}", ct)
+                    ty::ConstKind::Unevaluated(uv) => {
+                        Some(UnevaluatedConst { def: uv.def, args: uv.args, promoted: None })
                     }
                     _ => None,
                 },

compiler/rustc_mir_build/src/builder/expr/as_place.rs

@@ -651,8 +651,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // though. FIXME: Do we really *need* to count this as a use?
                 // Could partial array tracking work off something else instead?
                 self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place);
-                let const_ = Const::from_ty_const(*len_const, self.tcx.types.usize, self.tcx);
-                Operand::Constant(Box::new(ConstOperand { span, user_ty: None, const_ }))
+                Operand::Constant(Box::new(ConstOperand {
+                    span,
+                    user_ty: None,
+                    const_: Const::Ty(self.tcx.types.usize, *len_const),
+                }))
             }
             ty::Slice(_elem_ty) => {
                 let ptr_or_ref = if let [PlaceElem::Deref] = place.projection[..]