rust/src/test/ui/parser/byte-string-literals.rs

static FOO: &'static [u8] = b"\f";  //~ ERROR unknown byte escape

pub fn main() {
    b"\f";  //~ ERROR unknown byte escape
    b"\x0Z";  //~ ERROR invalid character in numeric character escape: Z
    b"é";  //~ ERROR byte constant must be ASCII
    b"a  //~ ERROR unterminated double quote byte string
}