Workaround for refcheck with subcaptions

Question

This question mentions a conflict between refcheck, subcaption and hyperref, and proposes a patch to help deal with some issues due to hyperref.

I would like to know if there is a workaround for the issue with refcheck and subcaption, in that refcheck warns about unused labels due to the sub@ prefix.

For instance, in this MWE:

\documentclass[11pt]{report}

\usepackage{subcaption}
\usepackage{refcheck}

\begin{document}
Figure \ref{fig:1a}, inside Figure \ref{fig:1}.

\begin{figure}
  \begin{subfigure}{0.45\textwidth}
    \caption{A subcaption}
    \label{fig:1a}
  \end{subfigure}
  \caption{A caption}
  \label{fig:1}
\end{figure}

\end{document}

Both labels fig:1 and fig:1a are referenced, but refcheck still reports:

Package refcheck Warning: Unused label `sub@fig:1a' on input line 12.

Is there a way to avoid the warning?

Answer 1

This redefines the subcaption label command to always report the dummy label "sub@label" as used.

\documentclass[11pt]{report}

\usepackage{subcaption}
\usepackage{refcheck}

\makeatletter
\let\orig@subcaption@@label\subcaption@@label
\def\subcaption@@label#1#2{\usedref{sub@#2}\orig@subcaption@@label{#1}{#2}}
\makeatother

\begin{document}
Figure \ref{fig:1a}, inside Figure \ref{fig:1}.

\begin{figure}
  \begin{subfigure}{0.45\textwidth}
    \caption{A subcaption}
    \label{fig:1a}
  \end{subfigure}
  \caption{A caption}
  \label{fig:1}
\end{figure}

\end{document}