Steps to reproduce:
Visit https://en.wikipedia.beta.wmflabs.org/wiki/Special:Contributions/DannyS712
"If you report this error to the Wikimedia System Administrators, please include the details below."
PHP fatal error:
Uncaught Error: Call to undefined method Diff\Differ\MapDiffer::setComparisonCallback() in /srv/mediawiki/php-master/extensions/WikibaseLexeme/src/Domain/Diff/LexemeDiffer.php:57
Stack trace:
#0 /srv/mediawiki/php-master/extensions/WikibaseLexeme/WikibaseLexeme.entitytypes.php(71): Wikibase\Lexeme\Domain\Diff\LexemeDiffer->__construct()
#1 [internal function]: Wikibase\Lexeme\WikibaseLexemeHooks::{closure}()
#2 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/WikibaseClient.php(1350): call_user_func(Object(Closure))
#3 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/WikibaseClient.php(1338): Wikibase\Client\WikibaseClient->getEntityDiffer()
#4 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/WikibaseClient.php(674): Wikibase\Client\WikibaseClient->getEntityChangeFactory()
#5 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/WikibaseClient.php(1320): Wikibase\Client\WikibaseClient->getStore()
#6 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/HoNotes:
Tested a few:
Does not occur on deploymentwiki or beta hewiktionary - don't have wikidata set up?
beta loginwiki returns 403 Forbidden Forbidden You don't have permission to access this resource. - could be a different issue?