Line 5, characters 18-27:
5 | let invalid_sv = "\u{0D800}" ;;
                      ^^^^^^^^^
Error: Illegal backslash escape in string or character (\u{0D800}): D800 is not a Unicode scalar value
Line 1, characters 18-26:
1 | let invalid_sv = "\u{D800}" ;;
                      ^^^^^^^^
Error: Illegal backslash escape in string or character (\u{D800}): D800 is not a Unicode scalar value
Line 1, characters 18-26:
1 | let invalid_sv = "\u{D900}" ;;
                      ^^^^^^^^
Error: Illegal backslash escape in string or character (\u{D900}): D900 is not a Unicode scalar value
Line 1, characters 18-26:
1 | let invalid_sv = "\u{DFFF}" ;;
                      ^^^^^^^^
Error: Illegal backslash escape in string or character (\u{DFFF}): DFFF is not a Unicode scalar value
Line 1, characters 18-28:
1 | let invalid_sv = "\u{110000} ;;
                      ^^^^^^^^^^
Error: Illegal backslash escape in string or character (\u{110000}): 110000 is not a Unicode scalar value
Line 2, characters 23-35:
2 | let too_many_digits = "\u{01234567}" ;;
                           ^^^^^^^^^^^^
Error: Illegal backslash escape in string or character (\u{01234567}): too many digits, expected 1 to 6 hexadecimal digits
Line 1, characters 21-23:
1 | let no_hex_digits = "\u{}" ;;
                         ^^
Warning 14 [illegal-backslash]: illegal backslash escape in string.
  Hint: Single backslashes \ are reserved for escape sequences (\n, \r, ...).
  Did you check the list of OCaml escape sequences?
  To get a backslash character, escape it with a second backslash: \\.

val no_hex_digits : string = "\\u{}"
Line 1, characters 25-27:
1 | let illegal_hex_digit = "\u{u}" ;;
                             ^^
Warning 14 [illegal-backslash]: illegal backslash escape in string.
  Hint: Single backslashes \ are reserved for escape sequences (\n, \r, ...).
  Did you check the list of OCaml escape sequences?
  To get a backslash character, escape it with a second backslash: \\.

val illegal_hex_digit : string = "\\u{u}"