diff --git a/src/librustc/dep_graph/edges.rs b/src/librustc/dep_graph/edges.rs
index b12db11cb6a..241bec39256 100644
--- a/src/librustc/dep_graph/edges.rs
+++ b/src/librustc/dep_graph/edges.rs
@@ -14,7 +14,7 @@ use rustc_data_structures::stable_hasher::StableHasher;
 use std::env;
 use std::hash::Hash;
 use std::mem;
-use super::{DepGraphQuery, DepKind, DepNode};
+use super::{DepKind, DepNode};
 use super::debug::EdgeFilter;
 
 pub(super) struct DepGraphEdges {
@@ -89,10 +89,6 @@ impl DepGraphEdges {
         }
     }
 
-    fn id(&self, index: DepNodeIndex) -> DepNode {
-        self.nodes[index.index()]
-    }
-
     pub fn push_ignore(&mut self) {
         self.task_stack.push(OpenTask::Ignore);
     }
@@ -231,13 +227,6 @@ impl DepGraphEdges {
         self.read(dep_node);
     }
 
-    pub fn query(&self) -> DepGraphQuery {
-        let edges: Vec<_> = self.edges.iter()
-                                      .map(|&(i, j)| (self.id(i), self.id(j)))
-                                      .collect();
-        DepGraphQuery::new(&self.nodes, &edges)
-    }
-
     #[inline]
     pub fn add_edge(&mut self, source: DepNode, target: DepNode) {
         let source = self.get_or_create_node(source);
diff --git a/src/librustc/dep_graph/graph.rs b/src/librustc/dep_graph/graph.rs
index cc15922bc2e..07e3fb45cc6 100644
--- a/src/librustc/dep_graph/graph.rs
+++ b/src/librustc/dep_graph/graph.rs
@@ -140,7 +140,18 @@ impl DepGraph {
     }
 
     pub fn query(&self) -> DepGraphQuery {
-        self.data.as_ref().unwrap().edges.borrow().query()
+        let current_dep_graph = self.data.as_ref().unwrap().current.borrow();
+        let nodes: Vec<_> = current_dep_graph.nodes.iter().cloned().collect();
+        let mut edges = Vec::new();
+        for (index, edge_targets) in current_dep_graph.edges.iter_enumerated() {
+            let from = current_dep_graph.nodes[index];
+            for &edge_target in edge_targets {
+                let to = current_dep_graph.nodes[edge_target];
+                edges.push((from, to));
+            }
+        }
+
+        DepGraphQuery::new(&nodes[..], &edges[..])
     }
 
     pub fn in_ignore<'graph>(&'graph self) -> Option<raii::IgnoreTask<'graph>> {
diff --git a/src/librustc_incremental/assert_dep_graph.rs b/src/librustc_incremental/assert_dep_graph.rs
index 1d58d179960..acbd3e0d63d 100644
--- a/src/librustc_incremental/assert_dep_graph.rs
+++ b/src/librustc_incremental/assert_dep_graph.rs
@@ -209,7 +209,7 @@ fn check_paths<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     }
     let query = tcx.dep_graph.query();
     for &(_, source_def_id, ref source_dep_node) in if_this_changed {
-        let dependents = query.transitive_successors(source_dep_node);
+        let dependents = query.transitive_predecessors(source_dep_node);
         for &(target_span, ref target_pass, _, ref target_dep_node) in then_this_would_need {
             if !dependents.contains(&target_dep_node) {
                 tcx.sess.span_err(