[STRING_LITERAL](https://doc.rust-lang.org/reference/tokens.html#string-literals) definition says:  Where [_IsolatedCR_](https://doc.rust-lang.org/reference/comments.html#comments) is:  And [ASCII_ESCAPE](https://doc.rust-lang.org/reference/tokens.html#ascii-escapes) is:  But look, there is no compile time error:  My question: Is this a human error or some feature of the lexer implementation which I don't know about?