From 57d3a5a32de7a10ed7af886dc6ddd3754c9a394c Mon Sep 17 00:00:00 2001
From: Gabriel Smith <ga29smith@gmail.com>
Date: Thu, 28 Feb 2019 23:09:44 -0500
Subject: [PATCH] impl visit_const for HasEscapingVarsVisitor

Signed-off-by: Gabriel Smith <ga29smith@gmail.com>
---
 src/librustc/ty/fold.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/librustc/ty/fold.rs b/src/librustc/ty/fold.rs
index dd936efb3c8..96705124b28 100644
--- a/src/librustc/ty/fold.rs
+++ b/src/librustc/ty/fold.rs
@@ -32,6 +32,7 @@
 //! looking for, and does not need to visit anything else.
 
 use crate::hir::def_id::DefId;
+use crate::mir::interpret::ConstValue;
 use crate::ty::{self, Binder, Ty, TyCtxt, TypeFlags, flags::FlagComputation};
 
 use std::collections::BTreeMap;
@@ -840,6 +841,17 @@ fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
         // visited.
         r.bound_at_or_above_binder(self.outer_index)
     }
+
+    fn visit_const(&mut self, c: &'tcx ty::LazyConst<'tcx>) -> bool {
+        if let ty::LazyConst::Evaluated(ty::Const {
+            val: ConstValue::Infer(ty::InferConst::Canonical(debruijn, _)),
+            ..
+        }) = *c {
+            debruijn >= self.outer_index
+        } else {
+            false
+        }
+    }
 }
 
 struct HasTypeFlagsVisitor {
-- 
2.44.0