From 07345f041ee0bf7bdd0ea0395865872297725668 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Wed, 12 Dec 2018 09:34:43 +0100
Subject: [PATCH] Undo a change that got lost in the larger refactorings

---
 src/librustc_mir/transform/qualify_consts.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 0f54978c1dec..2caeba6c06a3 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -557,9 +557,11 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     match proj.elem {
                         ProjectionElem::Deref => {
                             if context.is_mutating_use() {
+                                // `not_const` errors out in const contexts
                                 this.not_const()
                             } else {
-                                this.qualif = Qualif::NOT_CONST;
+                                // just make sure this doesn't get promoted
+                                this.qualif.add(Qualif::NOT_CONST);
                             }
                             let base_ty = proj.base.ty(this.mir, this.tcx).to_ty(this.tcx);
                             match this.mode {