diff --git a/arangod/Aql/TraversalConditionFinder.cpp b/arangod/Aql/TraversalConditionFinder.cpp
index a4e26c32e3..6357ef9214 100644
--- a/arangod/Aql/TraversalConditionFinder.cpp
+++ b/arangod/Aql/TraversalConditionFinder.cpp
@@ -52,17 +52,14 @@ bool checkPathVariableAccessFeasible (CalculationNode const* cn,
 
   node->findVariableAccess(currentPath, paths, var);
 
-  for (auto onePath : paths) {
+  for (auto const& onePath : paths) {
     size_t len = onePath.size();
     bool isEdgeAccess = false;
-    bool isVertexAccess = false;
 
     if (onePath[len - 2]->type == NODE_TYPE_ATTRIBUTE_ACCESS) {
       isEdgeAccess   = strcmp(onePath[len - 2]->getStringValue(),    "edges") == 0;
-      isVertexAccess = strcmp(onePath[len - 2]->getStringValue(), "vertices") == 0;
-
-      if (!isEdgeAccess && ! isVertexAccess) {
 
+      if (!isEdgeAccess && strcmp(onePath[len - 2]->getStringValue(), "vertices") != 0) {
         /* We can't catch all cases in which this error would occur, so we don't throw here.
            std::string message("TRAVERSAL: path only knows 'edges' and 'vertices', not ");
            message += onePath[len - 2]->getStringValue();
diff --git a/arangod/Cluster/ClusterTraverser.h b/arangod/Cluster/ClusterTraverser.h
index 32cba8ef72..0113110880 100644
--- a/arangod/Cluster/ClusterTraverser.h
+++ b/arangod/Cluster/ClusterTraverser.h
@@ -92,7 +92,7 @@ namespace triagens {
 
             public:
 
-              VertexGetter (ClusterTraverser* traverser)
+              explicit VertexGetter (ClusterTraverser* traverser)
                 : _traverser(traverser) {
                 }
 
@@ -108,7 +108,7 @@ namespace triagens {
 
             public:
 
-              EdgeGetter (ClusterTraverser* traverser)
+              explicit EdgeGetter (ClusterTraverser* traverser)
                 : _traverser(traverser),
                   _continueConst(1) {
                 }
diff --git a/arangod/V8Server/V8Traverser.h b/arangod/V8Server/V8Traverser.h
index b03b3b84f5..7cfc0cae42 100644
--- a/arangod/V8Server/V8Traverser.h
+++ b/arangod/V8Server/V8Traverser.h
@@ -195,24 +195,24 @@ namespace triagens {
 // -----------------------------------------------------------------------------
 // --SECTION--                                                  public functions
 // -----------------------------------------------------------------------------
+
         public:
 
-          SingleServerTraversalPath (
-            const triagens::basics::EnumeratedPath<EdgeInfo, VertexId>& path
-          ) : _path(path) {
+          explicit SingleServerTraversalPath (triagens::basics::EnumeratedPath<EdgeInfo, VertexId> const& path) 
+            : _path(path) {
           }
 
           ~SingleServerTraversalPath () {
           }
 
-          triagens::basics::Json* pathToJson (Transaction*,
-                                              CollectionNameResolver*) override;
+          triagens::basics::Json* pathToJson (triagens::arango::Transaction*,
+                                              triagens::arango::CollectionNameResolver*) override;
 
-          triagens::basics::Json* lastEdgeToJson (Transaction*,
-                                                  CollectionNameResolver*) override;
+          triagens::basics::Json* lastEdgeToJson (triagens::arango::Transaction*,
+                                                  triagens::arango::CollectionNameResolver*) override;
 
-          triagens::basics::Json* lastVertexToJson (Transaction*,
-                                                    CollectionNameResolver*) override;
+          triagens::basics::Json* lastVertexToJson (triagens::arango::Transaction*,
+                                                    triagens::arango::CollectionNameResolver*) override;
 
         private:
 
diff --git a/arangod/VocBase/Legends.h b/arangod/VocBase/Legends.h
index 40ef785a02..f850a70240 100644
--- a/arangod/VocBase/Legends.h
+++ b/arangod/VocBase/Legends.h
@@ -236,7 +236,7 @@ namespace triagens {
         Shape const* _shapes;
 
       public:
-        LegendReader (char const* l) 
+        explicit LegendReader (char const* l) 
           : Shaper(),
             _legend(l) {
 
diff --git a/arangod/VocBase/Traverser.h b/arangod/VocBase/Traverser.h
index 9ed870b19c..a52d3d3b9d 100644
--- a/arangod/VocBase/Traverser.h
+++ b/arangod/VocBase/Traverser.h
@@ -113,7 +113,7 @@ namespace triagens {
               compareTo(nullptr) {
           }
 
-          TraverserExpression (TRI_json_t const*);
+          explicit TraverserExpression (TRI_json_t const*);
 
           virtual ~TraverserExpression () {
             // no need to destroy varAccess here. Its memory is managed via the