error when using symbols as endnote marks

Question

\documentclass{memoir}

\usepackage{endnotes}

% These work just fine:
%   \renewcommand{\theendnote}{\alph{endnote}}
%   \renewcommand{\theendnote}{\arabic{endnote}}
%   \renewcommand{\theendnote}{\Roman{endnote}}

% But this does not:
    \renewcommand{\theendnote}{\fnsymbol{endnote}}

\begin{document}

This is some text.\endnote{This is an endnote.}

\theendnotes

\end{document}

I'm using Linux Mint 18 with the packages "texworks" (0.5~svn1363-6build2) and "texlive-full" (2015.20160320-1). Prior to those releases, I had no problem getting symbols to work as endnote marks. Now, however, it brings up an error:

TeX capacity exceeded, sorry [input stack size=5000].
\font@name ->
    \OMS/cmr/m/n/7
l.15 ...is some text.\endnote{This is an endnote.}

I've tried the above MWE, and got the same results, so I assume it's not my code. I need to use both endnotes and footnotes, but in a non-traditional placement. The latter doesn't give me any trouble, just the former.

NEW ISSUE:

Egreg's solution worked for me. However, I then decided to try the "enotez" package as he suggested in a subsequent post, and now I'm back to the same issue!

\documentclass[12pt]{article}

\pagestyle{empty}
    \usepackage[counter-format=roman]{enotez} % This works.
%   \usepackage[counter-format=symbols]{enotez} % This does not.

\begin{document}

This is my first sentence.\endnote{A notation placed arbitrarily.}

This is my second sentence.%
\footnote{A reference placed at the bottom of the page.}%
\footnote{Another reference.}%
\footnote{Yet another.}

\DeclareInstance{enotez-list}{custom}{paragraph}{heading=\bigskip}
\printendnotes[custom]

\end{document}

Answer 1

Unfortunately, endnotes uses \write for its workings. You can fix the problem by defining a “better protected” version of \fnsymbol.

\documentclass{article}% or memoir or any other class

\usepackage{endnotes}

\makeatletter
\newcommand{\pfnsymbol}[1]{%
  \expandafter\@pfnsymbol\expandafter{\the\csname c@#1\endcsname}%
}
\protected\def\@pfnsymbol#1{\@fnsymbol{#1}}
\makeatother

\renewcommand{\theendnote}{\pfnsymbol{endnote}}

\begin{document}

This is some text.\endnote{This is an endnote.}

\theendnotes

\end{document}

Here's a “conceptually better” solution, which patches the errors in endnotes.sty rather than adding a layer at document level.

\documentclass{article}% or memoir or any other class

\usepackage{endnotes}
\usepackage{xpatch}

\makeatletter
% http://tex.stackexchange.com/a/192133/
% get a copy of `\protected@write
\let\protected@iwrite\protected@write
% patch the copy to add \immediate
\xpatchcmd{\protected@iwrite}{\write}{\immediate\write}{}{}

% patch endnotes to use \protected@iwrite instead of \immediate\write
\xpatchcmd{\@endnotetext}{\immediate\write\@enotes}{\protected@iwrite\@enotes{}}{}{}
\xpatchcmd{\@endnotetext}{\immediate\write\@enotes}{\protected@iwrite\@enotes{}}{}{}
\xpatchcmd{\@endnotetext}{\immediate\write\@enotes}{\protected@iwrite\@enotes{}}{}{}
% patch endnotes to use \protected@edef instead of \edef
\xpatchcmd{\theendnotes}{\edef\@currentlabel}{\protected@edef\@currentlabel}{}{\ddt}
\makeatother

\renewcommand{\theendnote}{\fnsymbol{endnote}}

\begin{document}

This is some text.\endnote{This is an endnote.}

\theendnotes

\end{document}