is duplicated by:

• SR-12769 lldb expression command prints wrong result for characters in the range 0x80-0x9f
• SR-13403 UTF-8 decoding truncates replacement character

Issue Description:

If I go into the REPL in Swift 4.1.2 (swiftlang-902.0.54 clang-902.0.39.2) and type in the string "\u{8d}" the REPL will instead echo

$R9: String = "\u{c2}"

back to me.

This doesn't seem to be a problem in the actual representation of the string: When I inspect the individual characters, the correct value is stored. Also, calling print with it works "fine" (it's not really a printable character, but at least it doesn't print "Â", which is what "\u{c2}" would resolve to).

(See also: https://forums.swift.org/t/weird-issue-when-printing-string-with-unicode-character/14001)