Case-insensitive search of russian text in PDF documents is broken (by commit 696b6bc6)
The problem: When searching for russian text in default (case-insensitive) mode, evince returns no results, unless case-sensitive search option is turned on. Other non-ASCII7 languages might be affected by this bug as well.
The problematic commit is: 696b6bc6. Test PDF file is here. Seems like it's an issue in Poppler IgnoreDiacritics option implementation.