POSIX Yacc whose use is reported by -Wyacc, and rejected in Yacc
mode (--yacc).
+** 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.
+
** Temporary hack for adding a semicolon to the user action.
Previously, Bison appended a semicolon to every user action for
were resolved with %nonassoc. Such tokens are now properly omitted
from the list.
+** Destructor calls fixed for lookaheads altered in semantic actions.
+
+ Previously for deterministic parsers in C, if a user semantic action
+ altered yychar, the parser in some cases used the old yychar value to
+ determine which destructor to call for the lookahead upon a syntax
+ error or upon parser return. This bug has been fixed.
+
* Changes in version 2.4.2 (????-??-??):
** Detection of GNU M4 1.4.6 or newer during configure is improved.