Why does the position of equation numbers depend on label length?

Question

The cleveref package allows users to specify label types using the command \crefname. Unfortunately, using these label types with the amsart or amsbook classes causes the position of the equation number to depend on the label length. How can I make equation number positioning independent of label length?

Concretely, if you consider the following MWE, then second equation number is to the left of the first, and the third is far to the left of the second. All equation numbers should be aligned under the first equation number.

\documentclass{amsart}
\usepackage{cleveref}

\crefname{foo}{bar}{baz}

\begin{document}
\begin{gather}
  \label{eq:a-really-long-label-but-equation-number-is-well-placed}
  \mathsf{blah blah blah blah blooh blooh blooh blooh} \to \mathsf{blah blah blah blah blah beep boop}
\end{gather}

\begin{gather}
  \label[foo]{eq:short-okish}
  \mathsf{blah blah blah blah blooh blooh blooh blooh} \to \mathsf{blah blah blah blah blah beep boop}
\end{gather}

\begin{gather}
  \label[foo]{eq:long-so-out-in-margin}
  \mathsf{blah blah blah blah blooh blooh blooh blooh} \to \mathsf{blah blah blah blah blah beep boop}
\end{gather}
\end{document}

Answer 1

It's a problem with cleveref that doesn't correctly patch \gmeasure@ and does

\let\label\@gobble

instead of using some macro that also gobbles an optional argument.

\documentclass{amsart}
\usepackage{cleveref}
\usepackage{xpatch}

\crefname{foo}{bar}{baz}

\makeatletter
\newcommand{\@gobbleoptone}[2][]{}
\xpatchcmd{\gmeasure@}{\let\label\@gobble}{\let\label\@gobbleoptone}{}{}
\makeatother

\begin{document}

\begin{gather}
  \mathsf{blah blah blah blah blooh blooh blooh blooh} \to \mathsf{blah blah blah blah blah beep boop}
  \label{eq:a-really-long-label-but-equation-number-is-well-placed}
\end{gather}

\begin{gather}
  \mathsf{blah blah blah blah blooh blooh blooh blooh} \to \mathsf{blah blah blah blah blah beep boop}
  \label[foo]{eq:short-okish}
\end{gather}

\begin{equation}
  \mathsf{blah blah blah blah blooh blooh blooh blooh} \to \mathsf{blah blah blah blah blah beep boop}
  \label[foo]{eq:long-so-out-in-margin}
\end{equation}

\end{document}