Unicode encoding is a rich source of strange behavior. A couple that come to mind: Decoders that try to restart on unexpected byte sequences: https://john-mill

Unicode encoding is a rich source of strange behavior. A couple that come to mind: Decoders that try to restart on unexpected byte sequences: https://john-millikin.com/%F0%9F%A4%94/case-report-surugaya-mojibake https://john-millikin.com/%F0%9F%A4%94/case-report-surugaya-... GHC 7.2 using Unicode to represent file paths on Linux (where paths are arbitrary bytes), an approach which was further explored in GHC 7.4 by using reserved codepoints. \u vs \U escapes in languages that added Unicode support before the codepoint space was expanded beyond 16 bits.