private void setTypeUsage(TypeMigrationUsageInfo usageInfo, PsiElement place) {
    if (place != null) {
      final Pair<TypeMigrationUsageInfo, TypeMigrationUsageInfo> rooted = Pair.create(usageInfo, myCurrentRoot);
      Set<PsiElement> usages = myRootUsagesTree.get(rooted);
      if (usages == null) {
        usages = new HashSet<>();
        myRootUsagesTree.put(rooted, usages);
      }
      usages.add(place);
    }
  }
private void setTypeUsage(TypeMigrationUsageInfo usageInfo, PsiElement place)