Titles containing consecutive single quotes are impossible to link to in the current implementation of the parser. As such, they should be disallowed (or the parser tweaked).
Test case: [[testwiki:User:MER-C/Sandbox]], linking to [[testwiki:''test]].
See also: [[WP:RAF#Disallow creating articles with multiple single quotes]].
Version: 1.16.x
Severity: normal