anchor.diff:    /// ```
     Token parseQualified(Token token, IdentifierContext context,
         IdentifierContext continuationContext) {
  -    token = ensureIdentifier(token.next, context);
  +    token = ensureIdentifier(token, context);
       while (optional('.', token.next)) {
         token = parseQualifiedRest(token, continuationContext);
       }
  
positive.code:         reportRecoverableError(next, fasta.messageAnnotationOnEnumConstant);
        }
        token =
            ensureIdentifier(token.next, IdentifierContext.enumValueDeclaration)
                .next;
        count++;
      } while (optional(',', token));
      expect('}', token);
  
negative.code:     assert(optional('enum', enumKeyword));
      listener.beginEnum(enumKeyword);
      token =
          ensureIdentifier(enumKeyword, IdentifierContext.enumDeclaration).next;
      Token leftBrace = token;
      expect('{', token);
      int count = 0;
  