! Package calc Error: `\let ' invalid at this point

Question

\documentclass[11pt,a4paper]{article}
\usepackage{polyglossia}
\setmainlanguage{portuges}
\setotherlanguages{english}

\usepackage{graphicx}
\usepackage{url}
\usepackage{hyperref}
\usepackage{enumitem}
\usepackage{pdfpages}

\def\UrlBreaks{\do-\do\/}
\usepackage{amssymb,latexsym,amsthm,amsfonts,color,fancyhdr}
\setlength{\parindent}{0pt}
\setlength{\parskip}{5pt}


\setlist[enumerate]{noitemsep, topsep=10pt, partopsep=20pt}
\setlist[enumerate,1]{label*=\enspace \arabic*.,before=\normalfont\mdseries,after=\normalfont,leftmargin=1.3em\large}
\setlist[enumerate,2]{label*=\arabic*.,before=\normalfont\upshape\normalsize,after=\normalfont}
\setlist[enumerate,3]{label*=\arabic*.,before=\normalfont\upshape,after=\normalfont}
\setlist[enumerate,4]{label*=\arabic*.,before=\normalfont\upshape,after=\normalfont}



%\makeindex

%\author{Luís Mendes}
\title{Informação }

\begin{document}


\iffalse
\begin{titlepage}
\begin{center}
\textsc{}
\\
\vspace{1cm}
\textsc{}
\\
\vspace{5cm}

\maketitle

\vspace{2cm}

1

{\large \emph{}}
\\
\vspace{5cm}

\begin{tabular}{l p{0.5\linewidth}}
Lu\\
()\\
\end{tabular}
\end{center}
\vspace*{\fill}


\end{titlepage}
\fi
% capa interior com menção dos orientadores
\thispagestyle{empty}



\newpage

\selectlanguage{portuges}
Proc
J

\vspace{1.5cm}

À Ex.\\
Ao Ex

\vspace{2cm}

Vila

\vspace{3.5cm}

E


\begin{enumerate}
\item {Quanto}

\end{enumerate}


\end{document}

What's wrong with this minimal example?

Answer 1

Your minimal example was not very minimal, removing packages unrelated to the problem a more specific example is

\documentclass[11pt,a4paper]{article}


\usepackage{enumitem}
\usepackage{calc}

\setlist[enumerate]{noitemsep, topsep=10pt, partopsep=20pt}
\setlist[enumerate,1]{label*=\enspace \arabic*.,before=\normalfont\mdseries,after=\normalfont,leftmargin=1.3em\large}


\begin{document}

\begin{enumerate}
\item {Quanto}

\end{enumerate}


\end{document}

The setting leftmargin=1.3em\large is in error, leftmargin has to take a length value, without the calc package being loaded the error is not trapped and it accidentally runs to completion, but with the calc package (from pdfpages) you get an error. In either case the spurious \large should be removed.