+## -------------- ##
+## Web2c Report. ##
+## -------------- ##
+
+# The generation of the reduction was once wrong in Bison, and made it
+# miss some reductions. In the following test case, the reduction on
+# `undef_id_tok' in state 1 was missing. This is stripped down from
+# the actual web2c.y.
+
+AT_SETUP([Web2c Report])
+
+AT_DATA([input.y],
+[[%token undef_id_tok const_id_tok
+
+%start CONST_DEC_PART
+\f
+%%
+CONST_DEC_PART:
+ CONST_DEC_LIST
+ ;
+
+CONST_DEC_LIST:
+ CONST_DEC
+ | CONST_DEC_LIST CONST_DEC
+ ;
+
+CONST_DEC:
+ { } undef_id_tok '=' const_id_tok ';'
+ ;
+%%
+
+]])
+
+AT_CHECK([bison -v input.y])
+
+AT_CHECK([sed -n 's/ *$//;/^$/!p' input.output], 0,
+[[Grammar
+ Number, Line, Rule
+ 0 6 $axiom -> CONST_DEC_PART $
+ 1 6 CONST_DEC_PART -> CONST_DEC_LIST
+ 2 10 CONST_DEC_LIST -> CONST_DEC
+ 3 12 CONST_DEC_LIST -> CONST_DEC_LIST CONST_DEC
+ 4 15 @1 -> /* empty */
+ 5 15 CONST_DEC -> @1 undef_id_tok '=' const_id_tok ';'
+Terminals, with rules where they appear
+$ (0) 0
+';' (59) 5
+'=' (61) 5
+error (256)
+undef_id_tok (257) 5
+const_id_tok (258) 5
+Nonterminals, with rules where they appear
+$axiom (7)
+ on left: 0
+CONST_DEC_PART (8)
+ on left: 1, on right: 0
+CONST_DEC_LIST (9)
+ on left: 2 3, on right: 1 3
+CONST_DEC (10)
+ on left: 5, on right: 2 3
+@1 (11)
+ on left: 4, on right: 5
+state 0
+ $default reduce using rule 4 (@1)
+ CONST_DEC_PART go to state 1
+ CONST_DEC_LIST go to state 2
+ CONST_DEC go to state 3
+ @1 go to state 4
+state 1
+ $axiom -> CONST_DEC_PART . $ (rule 0)
+ $ shift, and go to state 5
+state 2
+ CONST_DEC_PART -> CONST_DEC_LIST . (rule 1)
+ CONST_DEC_LIST -> CONST_DEC_LIST . CONST_DEC (rule 3)
+ undef_id_tok reduce using rule 4 (@1)
+ $default reduce using rule 1 (CONST_DEC_PART)
+ CONST_DEC go to state 6
+ @1 go to state 4
+state 3
+ CONST_DEC_LIST -> CONST_DEC . (rule 2)
+ $default reduce using rule 2 (CONST_DEC_LIST)
+state 4
+ CONST_DEC -> @1 . undef_id_tok '=' const_id_tok ';' (rule 5)
+ undef_id_tok shift, and go to state 7
+state 5
+ $axiom -> CONST_DEC_PART $ . (rule 0)
+ $default accept
+state 6
+ CONST_DEC_LIST -> CONST_DEC_LIST CONST_DEC . (rule 3)
+ $default reduce using rule 3 (CONST_DEC_LIST)
+state 7
+ CONST_DEC -> @1 undef_id_tok . '=' const_id_tok ';' (rule 5)
+ '=' shift, and go to state 8
+state 8
+ CONST_DEC -> @1 undef_id_tok '=' . const_id_tok ';' (rule 5)
+ const_id_tok shift, and go to state 9
+state 9
+ CONST_DEC -> @1 undef_id_tok '=' const_id_tok . ';' (rule 5)
+ ';' shift, and go to state 10
+state 10
+ CONST_DEC -> @1 undef_id_tok '=' const_id_tok ';' . (rule 5)
+ $default reduce using rule 5 (CONST_DEC)
+]])
+
+AT_CLEANUP
+
+
+## --------------- ##
+## Web2c Actions. ##
+## --------------- ##
+
+# The generation of the mapping `state -> action' was once wrong in
+# extremely specific situations. web2c.y exhibits this situation.
+# Below is a stripped version of the grammar. It looks like one can
+# simplify it further, but just don't: it is tuned to exhibit a bug,
+# which disapears when applying sane grammar transformations.
+#
+# It used to be wrong on yydefact only:
+#
+# static const short yydefact[] =
+# {
+# - 2, 0, 1, 0, 0, 2, 3, 2, 5, 4,
+# + 2, 0, 1, 0, 0, 0, 3, 2, 5, 4,
+# 0, 0
+# };
+#
+# but let's check all the tables.
+
+
+AT_SETUP([Web2c Actions])
+
+AT_DATA([input.y],
+[[%%
+statement: struct_stat;
+struct_stat: /* empty. */ | if else;
+if: "if" "const" "then" statement;
+else: "else" statement;
+%%
+]])
+
+AT_CHECK([bison -v input.y -o input.c])
+
+# Check only the tables. We don't use --no-parser, because it is
+# still to be implemented in the experimental branch of Bison.
+AT_CHECK([[sed -n 's/ *$//;/^static const.*\[\] =/,/^}/p' input.c]], 0,
+[[static const char yytranslate[] =
+{
+ 0, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 1, 3, 4, 5,
+ 6
+};
+static const short yyprhs[] =
+{
+ 0, 0, 3, 5, 6, 9, 14
+};
+static const short yyrhs[] =
+{
+ 8, 0, -1, 9, -1, -1, 10, 11, -1, 3,
+ 4, 5, 8, -1, 6, 8, -1
+};
+static const short yyrline[] =
+{
+ 0, 2, 2, 3, 3, 4, 5
+};
+static const char *const yytname[] =
+{
+ "$", "error", "$undefined.", "\"if\"", "\"const\"", "\"then\"",
+ "\"else\"", "$axiom", "statement", "struct_stat", "if", "else", NULL
+};
+static const short yytoknum[] =
+{
+ 0, 256, 2, 257, 258, 259, 260, -1
+};
+static const short yyr1[] =
+{
+ 0, 7, 8, 9, 9, 10, 11
+};
+static const short yyr2[] =
+{
+ 0, 2, 1, 0, 2, 4, 2
+};
+static const short yydefact[] =
+{
+ 3, 0, 0, 2, 0, 0, 0, 3, 4, 3,
+ 6, 5
+};
+static const short yydefgoto[] =
+{
+ -1, 2, 3, 4, 8
+};
+static const short yypact[] =
+{
+ -2, -1, 4,-32768, 0, 2,-32768, -2,-32768, -2,
+ -32768,-32768
+};
+static const short yypgoto[] =
+{
+ -32768, -7,-32768,-32768,-32768
+};
+static const short yytable[] =
+{
+ 10, 1, 11, 5, 6, 0, 7, 9
+};
+static const short yycheck[] =
+{
+ 7, 3, 9, 4, 0, -1, 6, 5
+};
+]])
+
+AT_CLEANUP