I copied some text from a web page into a comment and I get the error
"Error: Outside Unicode code space".
This appears to be an incorrect error message. It is upset about double quotes that lean forward or backwards, and apostrophes that lean backwards. And dashes that aren't the keyboard dash character.
The editor I am using (Code::Blocks) displays the characters just fine. So it seems that the error message should be "Error: Outside the ASCII code space".