diff --git a/src/parse.rs b/src/parse.rs
index 752544c..c0579ff 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -529,7 +529,11 @@ fn raw_byte_string(input: Cursor) -> Result<Cursor, Reject> {
                 Some((_, '\n')) => {}
                 _ => break,
             },
-            _ => {}
+            other => {
+                if !other.is_ascii() {
+                    break;
+                }
+            }
         }
     }
     Err(Reject)
diff --git a/tests/test.rs b/tests/test.rs
index 4934769..ca8a31d 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -163,7 +163,7 @@ fn literal_byte_string() {
     "b\"\\\r\n    x\"".parse::<TokenStream>().unwrap();
     "b\"\\\r\n  \rx\"".parse::<TokenStream>().unwrap_err();
     "b\"\\\r\n  \u{a0}x\"".parse::<TokenStream>().unwrap_err();
-    "br\"\u{a0}\"".parse::<TokenStream>().unwrap(); // FIXME
+    "br\"\u{a0}\"".parse::<TokenStream>().unwrap_err();
 }
 
 #[test]