diff --git a/moses/src/TargetBigramFeature.cpp b/moses/src/TargetBigramFeature.cpp
index 16932e590..9d6d755d5 100644
--- a/moses/src/TargetBigramFeature.cpp
+++ b/moses/src/TargetBigramFeature.cpp
@@ -4,7 +4,9 @@ namespace Moses {
 
 using namespace std;
 
-TargetBigramFeature::TargetBigramFeature(ScoreIndexManager &scoreIndexManager);
+TargetBigramFeature::TargetBigramFeature(ScoreIndexManager &scoreIndexManager)
+{
+}
 
 size_t TargetBigramFeature::GetNumScoreComponents() const
 {
@@ -31,15 +33,15 @@ size_t TargetBigramFeature::GetNumInputScores() const
 }
 
 
-virtual const FFState* TargetBigramFeature::EmptyHypothesisState(const InputType &input) const
+const FFState* TargetBigramFeature::EmptyHypothesisState(const InputType &input) const
 {
 	// TODO
 	return 0;
 }
 
-virtual FFState* TargetBigramFeature::Evaluate(const Hypothesis& cur_hypo,
-                                               const FFState* prev_state,
-                                               ScoreComponentCollection* accumulator) const
+FFState* TargetBigramFeature::Evaluate(const Hypothesis& cur_hypo,
+                                       const FFState* prev_state,
+                                       ScoreComponentCollection* accumulator) const
 {
 	// TODO
 	return 0;
diff --git a/moses/src/TargetBigramFeature.h b/moses/src/TargetBigramFeature.h
index 47b92a21c..fcc30cd04 100644
--- a/moses/src/TargetBigramFeature.h
+++ b/moses/src/TargetBigramFeature.h
@@ -1,9 +1,13 @@
 #ifndef moses_TargetBigramFeature_h
 #define moses_TargetBigramFeature_h
+
+#include "FeatureFunction.h"
+#include "FFState.h"
+#include <string>
+
 namespace Moses
 {
 
-
 /** Sets the features of observed bigrams.
  */
 class TargetBigramFeature : public StatefulFeatureFunction {