Finish implementing char validation

crates/ra_syntax/src/yellow/syntax_error.rs

@@ -69,6 +69,14 @@ pub enum SyntaxErrorKind {
     LongChar,
     EmptyAsciiEscape,
     InvalidAsciiEscape,
+    TooShortAsciiCodeEscape,
+    AsciiCodeEscapeOutOfRange,
+    MalformedAsciiCodeEscape,
+    UnclosedUnicodeEscape,
+    MalformedUnicodeEscape,
+    EmptyUnicodeEcape,
+    OverlongUnicodeEscape,
+    UnicodeEscapeOutOfRange,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -83,6 +91,14 @@ impl fmt::Display for SyntaxErrorKind {
             EmptyChar => write!(f, "Empty char literal"),
             UnclosedChar => write!(f, "Unclosed char literal"),
             LongChar => write!(f, "Char literal should be one character long"),
+            TooShortAsciiCodeEscape => write!(f, "Escape sequence should have two digits"),
+            AsciiCodeEscapeOutOfRange => write!(f, "Escape sequence should be between \\x00 and \\x7F"),
+            MalformedAsciiCodeEscape => write!(f, "Escape sequence should be a hexadecimal number"),
+            UnclosedUnicodeEscape => write!(f, "Missing `}}`"),
+            MalformedUnicodeEscape => write!(f, "Malformed unicode escape sequence"),
+            EmptyUnicodeEcape => write!(f, "Empty unicode escape sequence"),
+            OverlongUnicodeEscape => write!(f, "Unicode escape sequence should have at most 6 digits"),
+            UnicodeEscapeOutOfRange => write!(f, "Unicode escape code should be at most 0x10FFFF"),
             ParseError(msg) => write!(f, "{}", msg.0),
         }
     }