Create new error code E0762 for unterminated char literals

src/librustc_error_codes/error_codes.rs

@@ -440,6 +440,7 @@ E0754: include_str!("./error_codes/E0754.md"),
 E0758: include_str!("./error_codes/E0758.md"),
 E0760: include_str!("./error_codes/E0760.md"),
 E0761: include_str!("./error_codes/E0761.md"),
+E0762: include_str!("./error_codes/E0762.md"),
 ;
 //  E0006, // merged with E0005
 //  E0008, // cannot bind by-move into a pattern guard

src/librustc_error_codes/error_codes/E0762.md

@@ -0,0 +1,13 @@
+A character literal wasn't ended with a quote.
+
+Erroneous code example:
+
+```compile_fail,E0762
+static C: char = '●; // error!
+```
+
+To fix this error, add the missing quote:
+
+```
+static C: char = '●'; // ok!
+```

src/librustc_parse/lexer/mod.rs

@@ -325,7 +325,15 @@ impl<'a> StringReader<'a> {
         let (lit_kind, mode, prefix_len, postfix_len) = match kind {
             rustc_lexer::LiteralKind::Char { terminated } => {
                 if !terminated {
-                    self.fatal_span_(start, suffix_start, "unterminated character literal").raise()
+                    self.sess
+                        .span_diagnostic
+                        .struct_span_fatal_with_code(
+                            self.mk_sp(start, suffix_start),
+                            "unterminated character literal",
+                            error_code!(E0762),
+                        )
+                        .emit();
+                    FatalError.raise();
                 }
                 (token::Char, Mode::Char, 1, 1) // ' '
             }