diff --git a/bootstrap/glob.go b/bootstrap/glob.go
index 77de891..a766676 100644
--- a/bootstrap/glob.go
+++ b/bootstrap/glob.go
@@ -237,6 +237,8 @@ func generateGlobNinjaFile(glob *GlobSingleton, config interface{}) ([]byte, []e
 		return nil, errs
 	}
 
+	// PrepareBuildActions() will write $OUTDIR/soong/globs/$m/$i files
+	// where $m=bp2build|build and $i=0..numGlobBuckets
 	extraDeps, errs = ctx.PrepareBuildActions(config)
 	if len(extraDeps) > 0 {
 		return nil, []error{fmt.Errorf("shouldn't have extra deps")}
diff --git a/metrics/event_handler.go b/metrics/event_handler.go
index f3641b0..3fd0f37 100644
--- a/metrics/event_handler.go
+++ b/metrics/event_handler.go
@@ -98,12 +98,12 @@ func (h *EventHandler) CompletedEvents() []Event {
 			h.scopeIds))
 	}
 	// Validate no two events have the same full id.
-	ids := map[string]bool{}
+	ids := map[string]struct{}{}
 	for _, event := range h.completedEvents {
 		if _, containsId := ids[event.Id]; containsId {
 			panic(fmt.Errorf("Duplicate event registered: %s", event.Id))
 		}
-		ids[event.Id] = true
+		ids[event.Id] = struct{}{}
 	}
 	return h.completedEvents
 }