diff --git a/probe/docker/reporter.go b/probe/docker/reporter.go
index 587fcff28..734fb3c3f 100644
--- a/probe/docker/reporter.go
+++ b/probe/docker/reporter.go
@@ -29,13 +29,13 @@ func NewReporter(registry Registry, scope string) *Reporter {
 // Report generates a Report containing Container and ContainerImage topologies
 func (r *Reporter) Report() (report.Report, error) {
 	result := report.MakeReport()
-	result.Container.Merge(r.containerTopology())
-	result.ContainerImage.Merge(r.containerImageTopology())
+	result.Container = result.Container.Merge(r.containerTopology())
+	result.ContainerImage = result.ContainerImage.Merge(r.containerImageTopology())
 	return result, nil
 }
 
 func (r *Reporter) containerTopology() report.Topology {
-	result := report.NewTopology()
+	result := report.MakeTopology()
 
 	r.registry.WalkContainers(func(c Container) {
 		nodeID := report.MakeContainerNodeID(r.scope, c.ID())
@@ -46,7 +46,7 @@ func (r *Reporter) containerTopology() report.Topology {
 }
 
 func (r *Reporter) containerImageTopology() report.Topology {
-	result := report.NewTopology()
+	result := report.MakeTopology()
 
 	r.registry.WalkImages(func(image *docker_client.APIImages) {
 		nmd := report.MakeNodeMetadataWith(map[string]string{
diff --git a/probe/docker/tagger.go b/probe/docker/tagger.go
index 3badea8a0..201b317c8 100644
--- a/probe/docker/tagger.go
+++ b/probe/docker/tagger.go
@@ -83,6 +83,6 @@ func (t *Tagger) tag(tree process.Tree, topology *report.Topology) {
 			ContainerID: c.ID(),
 		})
 
-		topology.NodeMetadatas[nodeID].Merge(md)
+		topology.NodeMetadatas[nodeID] = nodeMetadata.Merge(md)
 	}
 }
diff --git a/probe/host/tagger.go b/probe/host/tagger.go
index 0776dc869..ac381012e 100644
--- a/probe/host/tagger.go
+++ b/probe/host/tagger.go
@@ -17,10 +17,10 @@ func NewTagger(hostID string) Tagger {
 
 // Tag implements Tagger.
 func (t Tagger) Tag(r report.Report) (report.Report, error) {
-	md := report.MakeNodeMetadataWith(map[string]string{report.HostNodeID: t.hostNodeID})
+	other := report.MakeNodeMetadataWith(map[string]string{report.HostNodeID: t.hostNodeID})
 	for _, topology := range r.Topologies() {
-		for nodeID := range topology.NodeMetadatas {
-			topology.NodeMetadatas[nodeID].Merge(md)
+		for id, md := range topology.NodeMetadatas {
+			topology.NodeMetadatas[id] = md.Merge(other)
 		}
 	}
 	return r, nil
diff --git a/probe/process/reporter.go b/probe/process/reporter.go
index dd595cbc2..28c9c99af 100644
--- a/probe/process/reporter.go
+++ b/probe/process/reporter.go
@@ -36,12 +36,12 @@ func (r *Reporter) Report() (report.Report, error) {
 	if err != nil {
 		return result, err
 	}
-	result.Process.Merge(processes)
+	result.Process = result.Process.Merge(processes)
 	return result, nil
 }
 
 func (r *Reporter) processTopology() (report.Topology, error) {
-	t := report.NewTopology()
+	t := report.MakeTopology()
 	err := r.walker.Walk(func(p Process) {
 		pidstr := strconv.Itoa(p.PID)
 		nodeID := report.MakeProcessNodeID(r.scope, pidstr)
diff --git a/probe/tag_report.go b/probe/tag_report.go
index 92d298259..cf1f240a1 100644
--- a/probe/tag_report.go
+++ b/probe/tag_report.go
@@ -50,9 +50,9 @@ func (topologyTagger) Tag(r report.Report) (report.Report, error) {
 		"host":            &(r.Host),
 		"overlay":         &(r.Overlay),
 	} {
-		md := report.MakeNodeMetadataWith(map[string]string{Topology: val})
-		for nodeID := range topology.NodeMetadatas {
-			(*topology).NodeMetadatas[nodeID].Merge(md)
+		other := report.MakeNodeMetadataWith(map[string]string{Topology: val})
+		for id, md := range topology.NodeMetadatas {
+			topology.NodeMetadatas[id] = md.Merge(other)
 		}
 	}
 	return r, nil