diff --git a/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs b/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
index b0346abee5a..6c796ea4c73 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
@@ -14,7 +14,7 @@
 //! context internal state.
 
 use std::io::{self, Write};
-use super::{Constraint, RegionInferenceContext};
+use super::{OutlivesConstraint, RegionInferenceContext};
 
 // Room for "'_#NNNNr" before things get misaligned.
 // Easy enough to fix if this ever doesn't seem like
@@ -79,7 +79,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let mut constraints: Vec<_> = self.constraints.iter().collect();
         constraints.sort();
         for constraint in &constraints {
-            let Constraint {
+            let OutlivesConstraint {
                 sup,
                 sub,
                 point,
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs b/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
index 6c4c02a36a0..c02e4ff3156 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
@@ -27,7 +27,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
 impl<'this, 'tcx> dot::Labeller<'this> for RegionInferenceContext<'tcx> {
     type Node = RegionVid;
-    type Edge = Constraint;
+    type Edge = OutlivesConstraint;
 
     fn graph_id(&'this self) -> dot::Id<'this> {
         dot::Id::new(format!("RegionInferenceContext")).unwrap()
@@ -41,31 +41,31 @@ impl<'this, 'tcx> dot::Labeller<'this> for RegionInferenceContext<'tcx> {
     fn node_label(&'this self, n: &RegionVid) -> dot::LabelText<'this> {
         dot::LabelText::LabelStr(format!("{:?}", n).into_cow())
     }
-    fn edge_label(&'this self, e: &Constraint) -> dot::LabelText<'this> {
+    fn edge_label(&'this self, e: &OutlivesConstraint) -> dot::LabelText<'this> {
         dot::LabelText::LabelStr(format!("{:?}", e.point).into_cow())
     }
 }
 
 impl<'this, 'tcx> dot::GraphWalk<'this> for RegionInferenceContext<'tcx> {
     type Node = RegionVid;
-    type Edge = Constraint;
+    type Edge = OutlivesConstraint;
 
     fn nodes(&'this self) -> dot::Nodes<'this, RegionVid> {
         let vids: Vec<RegionVid> = self.definitions.indices().collect();
         vids.into_cow()
     }
-    fn edges(&'this self) -> dot::Edges<'this, Constraint> {
+    fn edges(&'this self) -> dot::Edges<'this, OutlivesConstraint> {
         (&self.constraints.raw[..]).into_cow()
     }
 
     // Render `a: b` as `a <- b`, indicating the flow
     // of data during inference.
 
-    fn source(&'this self, edge: &Constraint) -> RegionVid {
+    fn source(&'this self, edge: &OutlivesConstraint) -> RegionVid {
         edge.sub
     }
 
-    fn target(&'this self, edge: &Constraint) -> RegionVid {
+    fn target(&'this self, edge: &OutlivesConstraint) -> RegionVid {
         edge.sup
     }
 }
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
index dea2683789b..d974a60c15c 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
@@ -68,7 +68,7 @@ pub struct RegionInferenceContext<'tcx> {
     dependency_map: Option<IndexVec<RegionVid, Option<ConstraintIndex>>>,
 
     /// The constraints we have accumulated and used during solving.
-    constraints: IndexVec<ConstraintIndex, Constraint>,
+    constraints: IndexVec<ConstraintIndex, OutlivesConstraint>,
 
     /// Type constraints that we check after solving.
     type_tests: Vec<TypeTest<'tcx>>,
@@ -118,11 +118,12 @@ pub(crate) enum Cause {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Constraint {
+pub struct OutlivesConstraint {
     // NB. The ordering here is not significant for correctness, but
     // it is for convenience. Before we dump the constraints in the
     // debugging logs, we sort them, and we'd like the "super region"
     // to be first, etc. (In particular, span should remain last.)
+
     /// The region SUP must outlive SUB...
     sup: RegionVid,
 
@@ -387,7 +388,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ) {
         debug!("add_outlives({:?}: {:?} @ {:?}", sup, sub, point);
         assert!(self.inferred_values.is_none(), "values already inferred");
-        self.constraints.push(Constraint {
+        self.constraints.push(OutlivesConstraint {
             span,
             sup,
             sub,
@@ -1139,7 +1140,7 @@ impl<'tcx> RegionDefinition<'tcx> {
     }
 }
 
-impl fmt::Debug for Constraint {
+impl fmt::Debug for OutlivesConstraint {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         write!(
             formatter,