Keep map hidden and instead move it out after visitor is finished

src/librustc_mir/transform/nll.rs

@@ -20,7 +20,7 @@ use std::collections::HashMap;
 
 #[allow(dead_code)]
 struct NLLVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
-    pub lookup_map: HashMap<RegionVid, Lookup>,
+    lookup_map: HashMap<RegionVid, Lookup>,
     infcx: InferCtxt<'a, 'gcx, 'tcx>,
 }
 
@@ -32,6 +32,10 @@ impl<'a, 'gcx, 'tcx> NLLVisitor<'a, 'gcx, 'tcx> {
         }
     }
 
+    pub fn into_results(self) -> HashMap<RegionVid, Lookup> {
+        self.lookup_map
+    }
+
     fn renumber_regions<T>(&self, value: &T) -> T where T: TypeFoldable<'tcx> {
         self.infcx.tcx.fold_regions(value, &mut false, |_region, _depth| {
             self.infcx.next_region_var(infer::MiscVariable(DUMMY_SP))
@@ -136,6 +140,7 @@ impl MirPass for NLL {
             let mut renumbered_mir = mir.clone();
             let mut visitor = NLLVisitor::new(infcx);
             visitor.visit_mir(&mut renumbered_mir);
+            let _results = visitor.into_results();
         })
     }
 }