diff --git a/src/common/bitpacker.rs b/src/common/bitpacker.rs
index 49ea9f9e6..7d7aeb23c 100644
--- a/src/common/bitpacker.rs
+++ b/src/common/bitpacker.rs
@@ -15,7 +15,7 @@ use std::ops::Deref;
 /// reasons, we want to ensure that a value spawns over at most 8 bytes
 /// of aligns bytes.
 ///
-/// Spawning over 9 bytes is possible for instance, if we do
+/// Spanning over 9 bytes is possible for instance, if we do
 /// bitpacking with an amplitude of 63 bits.
 /// In this case, the second int will start on bit
 /// 63 (which belongs to byte 7) and ends at byte 15;
diff --git a/src/fastfield/reader.rs b/src/fastfield/reader.rs
index aae1dd797..06190b111 100644
--- a/src/fastfield/reader.rs
+++ b/src/fastfield/reader.rs
@@ -1,20 +1,17 @@
 use std::io;
 use std::collections::HashMap;
 use directory::ReadOnlySource;
-use common::BinarySerializable;
+use common::{self, BinarySerializable};
+use common::bitpacker::{compute_num_bits, BitUnpacker};
 use DocId;
 use schema::{Field, SchemaBuilder};
 use std::path::Path;
 use schema::FAST;
 use directory::{WritePtr, RAMDirectory, Directory};
-use fastfield::FastFieldSerializer;
-use fastfield::FastFieldsWriter;
-use common::bitpacker::compute_num_bits;
-use common::bitpacker::BitUnpacker;
+use fastfield::{FastFieldSerializer, FastFieldsWriter};
 use schema::FieldType;
 use error::ResultExt;
 use std::mem;
-use common;
 use owning_ref::OwningRef;
 
 /// Trait for accessing a fastfield.
@@ -212,7 +209,7 @@ impl FastFieldReader for I64FastFieldReader {
         let output_u64: &mut [u64] = unsafe { mem::transmute(output) };
         self.underlying.get_range(start, output_u64);
         for mut_val in output_u64.iter_mut() {
-            *mut_val ^= 1 << 63;
+            *mut_val = common::u64_to_i64(*mut_val as u64) as u64;
         }
     }
 
diff --git a/src/postings/docset.rs b/src/postings/docset.rs
index ea4211a5f..22fa3d9f3 100644
--- a/src/postings/docset.rs
+++ b/src/postings/docset.rs
@@ -52,6 +52,18 @@ pub trait DocSet {
         }
     }
 
+    fn fill_buffer(&mut self, buffer: &mut [DocId]) -> bool {
+        for buffer_val in buffer.iter_mut() {
+            if self.advance() {
+                *buffer_val = self.doc();
+            }
+            else {
+                return false;
+            }
+        }
+        return true;
+    }
+
     /// Returns the current document
     fn doc(&self) -> DocId;
 
diff --git a/src/query/query.rs b/src/query/query.rs
index f091442a8..683281dc6 100644
--- a/src/query/query.rs
+++ b/src/query/query.rs
@@ -58,10 +58,8 @@ pub trait Query: fmt::Debug {
     /// - iterate throw the matched documents and push them to the collector.
     ///
     fn search(&self, searcher: &Searcher, collector: &mut Collector) -> Result<TimerTree> {
-
         let mut timer_tree = TimerTree::default();
         let weight = try!(self.weight(searcher));
-
         {
             let mut search_timer = timer_tree.open("search");
             for (segment_ord, segment_reader) in searcher.segment_readers().iter().enumerate() {