For consistency's sake I need to abbreviate all number-ranges in my document.
While biblatex can easily be made to abbreviate page ranges the equivalent command for the year ranges breaks compilation with Argument of \@secondoftwo has an extra }
\documentclass{article}
\usepackage{filecontents}
\begin{filecontents*}{mylibrary.bib}
@book{somebook1769,
Address = {Place},
Author = {Name, Given},
Title = {Some title of this publication},
Date = {1769/1783}}
}
\end{filecontents*}
\usepackage[style=authoryear,backend=biber]{biblatex}
\usepackage{csquotes}
\addbibresource{mylibrary.bib}
\DeclareFieldFormat{postnote}{\mkcomprange[{\mkpageprefix[pagination]}]{#1}}
\DeclareFieldFormat{pages}{\mkcomprange{#1}}
%%doesn't work:
%\DeclareFieldFormat{date}{\mkcomprange{#1}}
%%works (just for comparison)
%\DeclareFieldFormat{date}{\textbf{#1}}
\begin{document}
“some quote” from \cite[1348--1368]{somebook1769}
\printbibliography
\end{document}
(I tried to use
Year = {1769--83}}
which looks right but biblatex warns
WARN - year field '1769--83' in entry 'somebook1769' is not an integer - this will probably not sort properly.
and indeed the order of publications in the bibliography for several works by the same author is not correct.)

biblatexat some point. – Florian May 26 '19 at 20:04polyglossiaandxelatex. There seems to be a direct conflict betweenpolyglossia's english and your solution: It compiles all right but adds a space (quad?) before "Name". (There doesn't seem to be a problem with other languages.) If it is difficult to fix or you don't have the time right now, I should be able to switch tobabel, though. – Florian May 26 '19 at 20:14%. Should be fixed in the edit just now. The issue can occur with bothpolyglossiaandbabel, but due to some deficiencies withbiblatex'spolyglossiamodule (see https://tex.stackexchange.com/q/464281/35864) you may only have noticed it withpolyglossia. Generally I would advise to usebabelif at all possible and to only usepolyglossiaif it gives better results.polyglossiadevelopment has effectively stalled and many posts suggestingpolyglossiaare outdated. See also https://tex.stackexchange.com/q/482396/35864. – moewe May 26 '19 at 20:25polyglossiabut I have still quite some long-term projects using older code. Obviously it's about time to make an effort to cut the ties...) – Florian May 26 '19 at 20:56