let mut seen = (false, false);
for ch in src.chars() {
match ch {
- 'a' ... 'f' => seen.0 = true,
- 'A' ... 'F' => seen.1 = true,
+ 'a' ..= 'f' => seen.0 = true,
+ 'A' ..= 'F' => seen.1 = true,
'i' | 'u' => break, // start of suffix already
_ => ()
}