+** YYFAIL now produces warnings and Java parsers no longer implement it.
+
+ YYFAIL has existed for many years as an undocumented feature of
+ deterministic parsers in C generated by Bison. More recently, it was
+ a documented feature of Bison's experimental Java parsers. As
+ promised in Bison 2.4.2's NEWS entry, any appearance of YYFAIL in a
+ semantic action now produces a deprecation warning, and Java parsers
+ no longer implement YYFAIL at all. For further details, including a
+ discussion of how to suppress C preprocessor warnings about YYFAIL
+ being unused, see the Bison 2.4.2 NEWS entry.
+
+** `%prec IDENTIFIER' requires IDENTIFIER to be defined separately.
+
+ As promised in Bison 2.4.2's NEWS entry, it is now an error if a token
+ that appears after a %prec directive is not defined by %token, %left,
+ %right, or %nonassoc. This is required by POSIX.
+