Rollup merge of rust-lang#73280 - GuillaumeGomez:add-e0763, r=petrochenkov

Add E0763

Author: RalfJung

src/librustc_error_codes/error_codes.rs

@@ -443,6 +443,7 @@ E0759: include_str!("./error_codes/E0759.md"),
 E0760: include_str!("./error_codes/E0760.md"),
 E0761: include_str!("./error_codes/E0761.md"),
 E0762: include_str!("./error_codes/E0762.md"),
+E0763: include_str!("./error_codes/E0763.md"),
 ;
 //  E0006, // merged with E0005
 //  E0008, // cannot bind by-move into a pattern guard

src/librustc_error_codes/error_codes/E0763.md

@@ -0,0 +1,13 @@
+A byte constant wasn't correctly ended.
+
+Erroneous code example:
+
+```compile_fail,E0763
+let c = b'a; // error!
+```
+
+To fix this error, add the missing quote:
+
+```
+let c = b'a'; // ok!
+```

src/librustc_parse/lexer/mod.rs

@@ -339,8 +339,15 @@ impl<'a> StringReader<'a> {
             }
             rustc_lexer::LiteralKind::Byte { terminated } => {
                 if !terminated {
-                    self.fatal_span_(start + BytePos(1), suffix_start, "unterminated byte constant")
-                        .raise()
+                    self.sess
+                        .span_diagnostic
+                        .struct_span_fatal_with_code(
+                            self.mk_sp(start + BytePos(1), suffix_start),
+                            "unterminated byte constant",
+                            error_code!(E0763),
+                        )
+                        .emit();
+                    FatalError.raise();
                 }
                 (token::Byte, Mode::Byte, 2, 1) // b' '
             }

src/test/ui/parser/byte-literals.rs

@@ -8,5 +8,5 @@ pub fn main() {
     b'	';  //~ ERROR byte constant must be escaped
     b''';  //~ ERROR byte constant must be escaped
     b'é';  //~ ERROR byte constant must be ASCII
-    b'a  //~ ERROR unterminated byte constant
+    b'a  //~ ERROR unterminated byte constant [E0763]
 }

src/test/ui/parser/byte-literals.stderr

@@ -34,11 +34,12 @@ error: byte constant must be ASCII. Use a \xHH escape for a non-ASCII byte
 LL |     b'é';
    |       ^
 
-error: unterminated byte constant
+error[E0763]: unterminated byte constant
   --> $DIR/byte-literals.rs:11:6
    |
 LL |     b'a
    |      ^^^^
 
 error: aborting due to 7 previous errors
 
+For more information about this error, try `rustc --explain E0763`.