private void processInjectionHost(@NotNull UInjectionHost node) {
        PsiElement element = node.getSourcePsi();
        if (element == null) return;
        for (PsiReference reference : element.getReferences()) {
          if (reference instanceof PluginConfigReference &&
              !reference.isSoft() &&
              reference.resolve() == null) {
            holder.registerProblem(reference);
          }
        }
      }
private void processInjectionHost(@NotNull UInjectionHost node)