Clean up some compilation warnings.

src/lib.rs

@@ -101,7 +101,7 @@ impl<T: Hash + Eq + Clone, S, A> Graph<T, S, A> {
   /// calling `add_arc` with the new vertex `VertexId`.
   fn add_raw_vertex(&mut self, data: S) -> &mut RawVertex<S> {
     self.vertices.push(RawVertex {
-      data: data,
+      data,
       parents: Vec::new(),
       children: Vec::new(),
     });
@@ -115,9 +115,9 @@ impl<T: Hash + Eq + Clone, S, A> Graph<T, S, A> {
     self.get_vertex_mut(source).children.push(arc_id);
     self.get_vertex_mut(target).parents.push(arc_id);
     self.arcs.push(RawEdge {
-      data: data,
-      source: source,
-      target: target,
+      data,
+      source,
+      target,
     });
     arc_id
   }

src/mark_compact.rs

@@ -49,7 +49,7 @@ where
     }
   }
   unsafe { new_data.set_len(retained_count) }; // TODO: Maybe do this after each swap?
-  mem::replace(data, new_data);
+  *data = new_data;
 }
 
 /// Garbage collector state.
@@ -228,7 +228,7 @@ where
       arc_id_map[i].map(|id| id.as_usize())
     });
     // Reassign arc targets.
-    for mut arc in self.graph.arcs.iter_mut() {
+    for arc in self.graph.arcs.iter_mut() {
       arc.target = state_id_map[arc.target.as_usize()].unwrap();
     }
 

src/search.rs

@@ -127,7 +127,7 @@ impl<E: Error> Error for SearchError<E> {
     }
   }
 
-  fn cause(&self) -> Option<&Error> {
+  fn cause(&self) -> Option<&dyn Error> {
     match *self {
       SearchError::SelectionError(ref e) => Some(e),
       _ => None,