Prefer signed to unsigned integers

This patch contains more fixes to prefer signed to unsigned
integer types, as modern tools like 'gcc -fsanitize=undefined'
can check for signed integer overflow but not unsigned overflow.
* NEWS: Document the API change.
* boostrap.conf (gnulib_modules): Add intprops.
* data/skeletons/glr.c: Include stddef.h and stdint.h,
since this skeleton can assume C99 or later.
(YYSIZEMAX): Now signed, and the minimum of SIZE_MAX and PTRDIFF_MAX.
(yybool) [!__cplusplus]: Now signed (which is how bool behaves).
(YYTRANSLATE): Avoid use of unsigned, and make the macro
safe even for values greater than UINT_MAX.
(yytnamerr, struct yyGLRState, struct yyGLRStateSet, struct yyGLRStack)
(yyaddDeferredAction, yyinitStateSet, yyinitGLRStack)
(yyexpandGLRStack, yymarkStackDeleted, yyremoveDeletes)
(yyglrShift, yyglrShiftDefer, yy_reduce_print, yydoAction)
(yyglrReduce, yysplitStack, yyreportTree, yycompressStack)
(yyprocessOneStack, yyreportSyntaxError, yyrecoverSyntaxError)
(yyparse, yy_yypstack, yypstack, yypdumpstack):
* tests/input.at (Torturing the Scanner):
Prefer ptrdiff_t to size_t.
* data/skeletons/c++.m4 (b4_yytranslate_define):
* src/AnnotationList.c (AnnotationList__computePredecessorAnnotations):
* src/AnnotationList.h (AnnotationIndex):
* src/InadequacyList.h (InadequacyListNodeCount):
* src/closure.c (closure_new):
* src/complain.c (error_message, complains, complain_indent)
(complain_args, duplicate_directive, duplicate_rule_directive):
* src/gram.c (nritems, ritem_print, grammar_dump):
* src/ielr.c (ielr_compute_ritem_sees_lookahead_set)
(ielr_item_has_lookahead, ielr_compute_annotation_lists)
(ielr_compute_lookaheads):
* src/location.c (columns, boundary_print, location_print):
* src/muscle-tab.c (muscle_percent_define_insert)
(muscle_percent_define_check_values):
* src/output.c (prepare_rules, prepare_actions):
* src/parse-gram.y (id, handle_require):
* src/reader.c (record_merge_function_type, packgram):
* src/reduce.c (nuseless_productions, nuseless_nonterminals)
(inaccessable_symbols):
* src/relation.c (relation_print):
* src/scan-code.l (variant, variant_table_size, variant_count)
(variant_add, get_at_spec, show_sub_message, show_sub_messages)
(parse_ref):
* src/scan-gram.l (<SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>)
(scan_integer, convert_ucn_to_byte, handle_syncline):
* src/scan-skel.l (at_complain):
* src/symtab.c (complain_symbol_redeclared)
(complain_semantic_type_redeclared, complain_class_redeclared)
(symbol_class_set, complain_user_token_number_redeclared):
* src/tables.c (conflict_tos, conflrow, conflict_table)
(conflict_list, save_row, pack_vector):
* tests/local.at (AT_YYLEX_DEFINE(c)):
Prefer signed to unsigned integer.
* data/skeletons/lalr1.cc (yy_lac_check_):
* tests/actions.at (_AT_CHECK_PRINTER_AND_DESTRUCTOR):
* tests/local.at (AT_YYLEX_DEFINE(c)):
Omit now-unnecessary casts.
* data/skeletons/location.cc (b4_location_define):
* doc/bison.texi (Mfcalc Lexer, C++ position, C++ location):
Prefer int to unsigned for line and column numbers.
Change example to abort explicitly on memory exhaustion,
and fix an off-by-one bug that led to undefined behavior.
* data/skeletons/stack.hh (stack::operator[]):
Also allow ptrdiff_t indexes.
(stack::pop, slice::slice, slice::operator[]):
Index arg is now ptrdiff_t, not int.
(stack::ssize): New method.
(slice::range_): Now ptrdiff_t, not int.
* data/skeletons/yacc.c (b4_state_num_type): Remove.
All uses replaced by b4_int_type.
(YY_CONVERT_INT_BEGIN, YY_CONVERT_INT_END): New macros.
(yylac, yyparse): Use them around conversions that -Wconversion
would give false alarms about. 	Omit unnecessary casts.
(yy_stack_print): Use int rather than unsigned, and omit
a cast that doesn’t seem to be needed here any more.
* examples/c++/variant.yy (yylex):
* examples/c++/variant-11.yy (yylex):
Omit no-longer-needed conversions to unsigned.
* src/InadequacyList.c (InadequacyList__new_conflict):
Don’t assume *node_count is unsigned.
* src/output.c (muscle_insert_unsigned_table):
Remove; no longer used.

26 files changed, 109 insertions, 110 deletions

diff --git a/src/AnnotationList.c b/src/AnnotationList.c
index 4e29127c..cc6dc4f8 100644
--- a/src/AnnotationList.c
+++ b/src/AnnotationList.c
@@ -269,7 +269,7 @@ AnnotationList__computePredecessorAnnotations (
                   if (item_number_is_rule_number (ritem[s->items[self_item]
                                                         - 2]))
                     {
-                      unsigned rulei;
+                      int rulei;
                       for (rulei = s->items[self_item];
                            !item_number_is_rule_number (ritem[rulei]);
                            ++rulei)
diff --git a/src/AnnotationList.h b/src/AnnotationList.h
index ef3eeb6b..b0582fb1 100644
--- a/src/AnnotationList.h
+++ b/src/AnnotationList.h
@@ -25,7 +25,7 @@
 # include "InadequacyList.h"
 # include "state.h"
 
-typedef unsigned AnnotationIndex;
+typedef int AnnotationIndex;
 
 /**
  * A node in a list of annotations on a particular LR(0) state.  Each
diff --git a/src/InadequacyList.c b/src/InadequacyList.c
index 6caa14ea..ac608afa 100644
--- a/src/InadequacyList.c
+++ b/src/InadequacyList.c
@@ -22,6 +22,8 @@
 
 #include "InadequacyList.h"
 
+#include <intprops.h>
+
 ContributionIndex const ContributionIndex__none = -1;
 ContributionIndex const ContributionIndex__error_action = -2;
 
@@ -31,8 +33,9 @@ InadequacyList__new_conflict (state *manifesting_state, symbol *token,
                               InadequacyListNodeCount *node_count)
 {
   InadequacyList *result = xmalloc (sizeof *result);
-  result->id = (*node_count)++;
-  aver (*node_count != 0);
+  result->id = *node_count;
+  if (INT_ADD_WRAPV (*node_count, 1, node_count))
+    aver (false);
   result->next = NULL;
   result->manifestingState = manifesting_state;
   result->contributionCount = bitset_count (actions);
diff --git a/src/InadequacyList.h b/src/InadequacyList.h
index bb52f7ae..bc27df76 100644
--- a/src/InadequacyList.h
+++ b/src/InadequacyList.h
@@ -27,11 +27,8 @@
 
 /**
  * A unique ID assigned to every \c InadequacyList node.
- *
- * This must remain unsigned so that the overflow check in
- * \c InadequacyList__new_conflict works properly.
  */
-typedef unsigned long long InadequacyListNodeCount;
+typedef long long InadequacyListNodeCount;
 
 /**
  * For a conflict, each rule in the grammar can have at most one contributing
diff --git a/src/closure.c b/src/closure.c
index 0f46f834..b5ed6112 100644
--- a/src/closure.c
+++ b/src/closure.c
@@ -170,7 +170,7 @@ set_fderives (void)
 
 
 void
-closure_new (unsigned n)
+closure_new (int n)
 {
   itemset = xnmalloc (n, sizeof *itemset);
 
diff --git a/src/closure.h b/src/closure.h
index 1352a4ea..99dee91d 100644
--- a/src/closure.h
+++ b/src/closure.h
@@ -27,7 +27,7 @@
    data so that closure can be called.  n is the number of elements to
    allocate for itemset.  */
 
-void closure_new (unsigned n);
+void closure_new (int n);
 
 
 /* Given the kernel (aka core) of a state (a sorted vector of item numbers
diff --git a/src/complain.c b/src/complain.c
index 65a34671..ead8ebf7 100644
--- a/src/complain.c
+++ b/src/complain.c
@@ -417,10 +417,10 @@ warnings_print_categories (warnings warn_flags, FILE *out)
  */
 static
 void
-error_message (const location *loc, unsigned *indent, warnings flags,
+error_message (const location *loc, int *indent, warnings flags,
                severity sever, const char *message, va_list args)
 {
-  unsigned pos = 0;
+  int pos = 0;
 
   if (loc)
     pos += location_print (*loc, stderr);
@@ -470,7 +470,7 @@ error_message (const location *loc, unsigned *indent, warnings flags,
 /** Raise a complaint (fatal error, error or just warning).  */
 
 static void
-complains (const location *loc, unsigned *indent, warnings flags,
+complains (const location *loc, int *indent, warnings flags,
            const char *message, va_list args)
 {
   severity s = warning_severity (flags);
@@ -498,7 +498,7 @@ complain (location const *loc, warnings flags, const char *message, ...)
 }
 
 void
-complain_indent (location const *loc, warnings flags, unsigned *indent,
+complain_indent (location const *loc, warnings flags, int *indent,
                  const char *message, ...)
 {
   va_list args;
@@ -508,7 +508,7 @@ complain_indent (location const *loc, warnings flags, unsigned *indent,
 }
 
 void
-complain_args (location const *loc, warnings w, unsigned *indent,
+complain_args (location const *loc, warnings w, int *indent,
                int argc, char *argv[])
 {
   switch (argc)
@@ -563,7 +563,7 @@ void
 duplicate_directive (char const *directive,
                      location first, location second)
 {
-  unsigned i = 0;
+  int i = 0;
   if (feature_flag & feature_caret)
     complain_indent (&second, Wother, &i, _("duplicate directive"));
   else
@@ -577,7 +577,7 @@ void
 duplicate_rule_directive (char const *directive,
                           location first, location second)
 {
-  unsigned i = 0;
+  int i = 0;
   complain_indent (&second, complaint, &i,
                    _("only one %s allowed per rule"), directive);
   i += SUB_INDENT;
diff --git a/src/complain.h b/src/complain.h
index a7442547..4b73d08d 100644
--- a/src/complain.h
+++ b/src/complain.h
@@ -133,11 +133,11 @@ void complain (location const *loc, warnings flags, char const *message, ...)
   __attribute__ ((__format__ (__printf__, 3, 4)));
 
 /** Likewise, but with an \a argc/argv interface.  */
-void complain_args (location const *loc, warnings w, unsigned *indent,
+void complain_args (location const *loc, warnings w, int *indent,
                     int argc, char *arg[]);
 
 /** Make a complaint with location and some indentation.  */
-void complain_indent (location const *loc, warnings flags, unsigned *indent,
+void complain_indent (location const *loc, warnings flags, int *indent,
                       char const *message, ...)
   __attribute__ ((__format__ (__printf__, 4, 5)));
 
diff --git a/src/gram.c b/src/gram.c
index dd25da34..5753f70f 100644
--- a/src/gram.c
+++ b/src/gram.c
@@ -32,7 +32,7 @@
 /* Comments for these variables are in gram.h.  */
 
 item_number *ritem = NULL;
-unsigned nritems = 0;
+int nritems = 0;
 
 rule *rules = NULL;
 rule_number nrules = 0;
@@ -165,7 +165,7 @@ void
 ritem_print (FILE *out)
 {
   fputs ("RITEM\n", out);
-  for (unsigned i = 0; i < nritems; ++i)
+  for (int i = 0; i < nritems; ++i)
     if (ritem[i] >= 0)
       fprintf (out, "  %s", symbols[ritem[i]]->tag);
     else
@@ -280,8 +280,8 @@ grammar_dump (FILE *out, const char *title)
     for (rule_number i = 0; i < nrules + nuseless_productions; ++i)
       {
         rule const *rule_i = &rules[i];
-        unsigned const rhs_itemno = rule_i->rhs - ritem;
-        unsigned length = rule_rhs_length (rule_i);
+        int const rhs_itemno = rule_i->rhs - ritem;
+        int length = rule_rhs_length (rule_i);
         aver (item_number_as_rule_number (rule_i->rhs[length] == i));
         fprintf (out, "%3d (%2d, %2d, %2s, %2s)   %2d -> (%2u-%2u)",
                  i,
diff --git a/src/gram.h b/src/gram.h
index 0f0597ac..0f9ce3b5 100644
--- a/src/gram.h
+++ b/src/gram.h
@@ -115,7 +115,7 @@ extern int nvars;
 typedef int item_number;
 # define ITEM_NUMBER_MAX INT_MAX
 extern item_number *ritem;
-extern unsigned nritems;
+extern int nritems;
 
 /* There is weird relationship between OT1H item_number and OTOH
    symbol_number and rule_number: we store the latter in
diff --git a/src/ielr.c b/src/ielr.c
index 62df108e..24f60885 100644
--- a/src/ielr.c
+++ b/src/ielr.c
@@ -78,7 +78,7 @@ static bitset
 ielr_compute_ritem_sees_lookahead_set (void)
 {
   bitset result = bitset_create (nritems, BITSET_FIXED);
-  unsigned i = nritems-1;
+  int i = nritems-1;
   while (0 < i)
     {
       --i;
@@ -418,7 +418,7 @@ ielr_item_has_lookahead (state *s, symbol_number lhs, size_t item,
              top-level invocation), go get it.  */
           if (!lhs)
             {
-              unsigned i;
+              int i;
               for (i = s->items[item];
                    !item_number_is_rule_number (ritem[i]);
                    ++i)
@@ -496,7 +496,7 @@ ielr_compute_annotation_lists (bitsetv follow_kernel_items,
   AnnotationIndex *annotation_counts =
     xnmalloc (nstates, sizeof *annotation_counts);
   ContributionIndex max_contributions = 0;
-  unsigned total_annotations = 0;
+  int total_annotations = 0;
 
   *inadequacy_listsp = xnmalloc (nstates, sizeof **inadequacy_listsp);
   *annotation_listsp = xnmalloc (nstates, sizeof **annotation_listsp);
@@ -633,7 +633,7 @@ ielr_compute_lookaheads (bitsetv follow_kernel_items, bitsetv always_follows,
         {
           if (item_number_is_rule_number (ritem[t->items[t_item] - 2]))
             {
-              unsigned rule_item;
+              int rule_item;
               for (rule_item = t->items[t_item];
                    !item_number_is_rule_number (ritem[rule_item]);
                    ++rule_item)
diff --git a/src/location.c b/src/location.c
index bb2592f9..6bb7ba3b 100644
--- a/src/location.c
+++ b/src/location.c
@@ -60,8 +60,8 @@ columns (void)
   int res = 80;
   if (cp && *cp)
     {
-      unsigned long ul = strtoul (cp, NULL, 10);
-      res = ul < INT_MAX ? ul : INT_MAX;
+      long l = strtol (cp, NULL, 10);
+      res = 0 <= l && l <= INT_MAX ? l : INT_MAX;
     }
   else
     {
@@ -149,7 +149,7 @@ location_compute (location *loc, boundary *cur, char const *token, size_t size)
     complain (loc, Wother, _("byte number overflow"));
 }
 
-static unsigned
+static int
 boundary_print (boundary const *b, FILE *out)
 {
   return fprintf (out, "%s:%d.%d@%d",
@@ -157,10 +157,10 @@ boundary_print (boundary const *b, FILE *out)
                   b->line, b->column, b->byte);
 }
 
-unsigned
+int
 location_print (location loc, FILE *out)
 {
-  unsigned res = 0;
+  int res = 0;
   if (trace_flag & trace_locations)
     {
       res += boundary_print (&loc.start, out);
diff --git a/src/location.h b/src/location.h
index 64e80266..b9e4c726 100644
--- a/src/location.h
+++ b/src/location.h
@@ -112,7 +112,7 @@ void location_compute (location *loc,
 /* Print location to file.
    Return number of actually printed characters.
    Warning: uses quotearg's slot 3. */
-unsigned location_print (location loc, FILE *out);
+int location_print (location loc, FILE *out);
 
 /* Prepare the use of location_caret.  */
 void caret_init (void);
diff --git a/src/muscle-tab.c b/src/muscle-tab.c
index 91a45737..02c83530 100644
--- a/src/muscle-tab.c
+++ b/src/muscle-tab.c
@@ -525,7 +525,7 @@ muscle_percent_define_insert (char const *var, location variable_loc,
             = atoi (muscle_find_const (how_name));
           if (how_old == MUSCLE_PERCENT_DEFINE_F)
             goto end;
-          unsigned i = 0;
+          int i = 0;
           /* If assigning the same value, make it a warning.  */
           warnings warn = STREQ (value, current_value) ? Wother : complaint;
           complain_indent (&variable_loc, warn, &i,
@@ -739,7 +739,7 @@ muscle_percent_define_check_values (char const * const *values)
           if (!*values)
             {
               location loc = muscle_percent_define_get_loc (*variablep);
-              unsigned i = 0;
+              int i = 0;
               complain_indent (&loc, complaint, &i,
                                _("invalid value for %%define variable %s: %s"),
                                quote (*variablep), quote_n (1, value));
diff --git a/src/output.c b/src/output.c
index 85528beb..5eb1ffd1 100644
--- a/src/output.c
+++ b/src/output.c
@@ -91,7 +91,6 @@ Name (char const *name, Type *table_data, Type first,                   \
   MUSCLE_INSERT_LONG_INT (obstack_finish0 (&format_obstack), lmax);     \
 }
 
-GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_unsigned_table, unsigned)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_int_table, int)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_base_table, base_number)
 GENERATE_MUSCLE_INSERT_TABLE (muscle_insert_rule_number_table, rule_number)
@@ -214,17 +213,17 @@ prepare_symbols (void)
 static void
 prepare_rules (void)
 {
-  unsigned *prhs = xnmalloc (nrules, sizeof *prhs);
+  int *prhs = xnmalloc (nrules, sizeof *prhs);
   item_number *rhs = xnmalloc (nritems, sizeof *rhs);
-  unsigned *rline = xnmalloc (nrules, sizeof *rline);
+  int *rline = xnmalloc (nrules, sizeof *rline);
   symbol_number *r1 = xnmalloc (nrules, sizeof *r1);
-  unsigned *r2 = xnmalloc (nrules, sizeof *r2);
+  int *r2 = xnmalloc (nrules, sizeof *r2);
   int *dprec = xnmalloc (nrules, sizeof *dprec);
   int *merger = xnmalloc (nrules, sizeof *merger);
   int *immediate = xnmalloc (nrules, sizeof *immediate);
 
   /* Index in RHS.  */
-  unsigned i = 0;
+  int i = 0;
   for (rule_number r = 0; r < nrules; ++r)
     {
       /* Index of rule R in RHS. */
@@ -251,10 +250,10 @@ prepare_rules (void)
   aver (i == nritems);
 
   muscle_insert_item_number_table ("rhs", rhs, ritem[0], 1, nritems);
-  muscle_insert_unsigned_table ("prhs", prhs, 0, 0, nrules);
-  muscle_insert_unsigned_table ("rline", rline, 0, 0, nrules);
+  muscle_insert_int_table ("prhs", prhs, 0, 0, nrules);
+  muscle_insert_int_table ("rline", rline, 0, 0, nrules);
   muscle_insert_symbol_number_table ("r1", r1, 0, 0, nrules);
-  muscle_insert_unsigned_table ("r2", r2, 0, 0, nrules);
+  muscle_insert_int_table ("r2", r2, 0, 0, nrules);
   muscle_insert_int_table ("dprec", dprec, 0, 0, nrules);
   muscle_insert_int_table ("merger", merger, 0, 0, nrules);
   muscle_insert_int_table ("immediate", immediate, 0, 0, nrules);
@@ -542,10 +541,10 @@ prepare_actions (void)
      parser, so we could avoid accidents by not writing them out in
      that case.  Nevertheless, it seems even better to be able to use
      the GLR skeletons even without the non-deterministic tables.  */
-  muscle_insert_unsigned_table ("conflict_list_heads", conflict_table,
-                                conflict_table[0], 1, high + 1);
-  muscle_insert_unsigned_table ("conflicting_rules", conflict_list,
-                                0, 1, conflict_list_cnt);
+  muscle_insert_int_table ("conflict_list_heads", conflict_table,
+                           conflict_table[0], 1, high + 1);
+  muscle_insert_int_table ("conflicting_rules", conflict_list,
+                           0, 1, conflict_list_cnt);
 }
 
 
diff --git a/src/parse-gram.y b/src/parse-gram.y
index 06a83729..b4132841 100644
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -743,7 +743,7 @@ id:
         }
       if (muscle_percent_define_ifdef (var))
         {
-          unsigned indent = 0;
+          int indent = 0;
           complain_indent (&@1, complaint, &indent,
                            _("character literals cannot be used together"
                              " with %s"), var);
@@ -981,7 +981,7 @@ handle_require (location const *loc, char const *version)
      is the same as "3.0". */
   errno = 0;
   char* cp = NULL;
-  unsigned long major = strtoul (version, &cp, 10);
+  long major = strtol (version, &cp, 10);
   if (errno || *cp != '.')
     {
       complain (loc, complaint, _("invalid version requirement: %s"),
@@ -989,7 +989,7 @@ handle_require (location const *loc, char const *version)
       return;
     }
   ++cp;
-  unsigned long minor = strtoul (cp, NULL, 10);
+  long minor = strtol (cp, NULL, 10);
   if (errno)
     {
       complain (loc, complaint, _("invalid version requirement: %s"),
diff --git a/src/reader.c b/src/reader.c
index 43ca2036..928c8a7a 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -124,7 +124,7 @@ record_merge_function_type (int merger, uniqstr type, location declaration_loc)
   aver (merge_function != NULL && merger_find == merger);
   if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
     {
-      unsigned indent = 0;
+      int indent = 0;
       complain_indent (&declaration_loc, complaint, &indent,
                        _("result type clash on merge function %s: "
                          "<%s> != <%s>"),
@@ -611,7 +611,7 @@ grammar_current_rule_expect_rr (int count, location loc)
 static void
 packgram (void)
 {
-  unsigned itemno = 0;
+  int itemno = 0;
   ritem = xnmalloc (nritems + 1, sizeof *ritem);
   /* This sentinel is used by build_relations in gram.c.  */
   *ritem++ = 0;
diff --git a/src/reduce.c b/src/reduce.c
index 55f6a767..7dcfacfd 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -52,8 +52,8 @@ static bitset V;
    'useless', but no warning should be issued).  */
 static bitset V1;
 
-unsigned nuseless_productions;
-unsigned nuseless_nonterminals;
+int nuseless_productions;
+int nuseless_nonterminals;
 
 #define bitset_swap(Lhs, Rhs)                   \
   do {                                          \
@@ -195,10 +195,10 @@ inaccessable_symbols (void)
   bitset_free (P);
   P = Pp;
 
-  unsigned nuseful_productions = bitset_count (P);
+  int nuseful_productions = bitset_count (P);
   nuseless_productions = nrules - nuseful_productions;
 
-  unsigned nuseful_nonterminals = 0;
+  int nuseful_nonterminals = 0;
   for (symbol_number i = ntokens; i < nsyms; ++i)
     nuseful_nonterminals += bitset_test (V, i);
   nuseless_nonterminals = nvars - nuseful_nonterminals;
diff --git a/src/reduce.h b/src/reduce.h
index 9814962d..68105559 100644
--- a/src/reduce.h
+++ b/src/reduce.h
@@ -36,7 +36,7 @@ void reduce_free (void);
  * reduce_grammar.  Size nvars + nuseless_nonterminals.  */
 extern symbol_number *nterm_map;
 
-extern unsigned nuseless_nonterminals;
-extern unsigned nuseless_productions;
+extern int nuseless_nonterminals;
+extern int nuseless_productions;
 
 #endif /* !REDUCE_H_ */
diff --git a/src/relation.c b/src/relation.c
index 24f7a473..ebd3f216 100644
--- a/src/relation.c
+++ b/src/relation.c
@@ -33,14 +33,14 @@ relation_print (const char *title,
 {
   if (title)
     fprintf (out, "%s:\n", title);
-  for (size_t i = 0; i < size; ++i)
+  for (relation_node i = 0; i < size; ++i)
     if (r[i])
       {
         fputs ("    ", out);
         if (print)
           print (i, out);
         else
-          fprintf (out, "%3lu", (unsigned long) i);
+          fprintf (out, "%3ld", (long) i);
         fputc (':', out);
         for (relation_node j = 0; r[i][j] != END_NODE; ++j)
           {
@@ -48,7 +48,7 @@ relation_print (const char *title,
             if (print)
               print (r[i][j], out);
             else
-              fprintf (out, "%3lu", (unsigned long) r[i][j]);
+              fprintf (out, "%3ld", (long) r[i][j]);
           }
         fputc ('\n', out);
       }
diff --git a/src/scan-code.l b/src/scan-code.l
index 07f1117a..5fae172a 100644
--- a/src/scan-code.l
+++ b/src/scan-code.l
@@ -223,7 +223,7 @@ contains_dot_or_dash (const char* p)
 typedef struct
 {
   /* Index in symbol list. */
-  unsigned symbol_index;
+  int symbol_index;
 
   /* Matched symbol id and loc. */
   uniqstr id;
@@ -250,8 +250,8 @@ typedef struct
 #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
 
 static variant *variant_table = NULL;
-static unsigned variant_table_size = 0;
-static unsigned variant_count = 0;
+static int variant_table_size = 0;
+static int variant_count = 0;
 
 static variant *
 variant_table_grow (void)
@@ -286,7 +286,7 @@ find_prefix_end (char const *prefix, char const *cp, char const *end)
 }
 
 static variant *
-variant_add (uniqstr id, location id_loc, unsigned symbol_index,
+variant_add (uniqstr id, location id_loc, int symbol_index,
              char const *cp, char const *cp_end, bool explicit_bracketing)
 {
   char const *prefix_end = find_prefix_end (id, cp, cp_end);
@@ -307,7 +307,7 @@ variant_add (uniqstr id, location id_loc, unsigned symbol_index,
 }
 
 static const char *
-get_at_spec(unsigned symbol_index)
+get_at_spec(int symbol_index)
 {
   static char at_buf[20];
   if (symbol_index == 0)
@@ -321,7 +321,7 @@ static void
 show_sub_message (warnings warning,
                   const char* cp, bool explicit_bracketing,
                   int midrule_rhs_index, char dollar_or_at,
-                  unsigned indent, const variant *var)
+                  int indent, const variant *var)
 {
   const char *at_spec = get_at_spec (var->symbol_index);
 
@@ -385,9 +385,9 @@ static void
 show_sub_messages (warnings warning,
                    const char* cp, bool explicit_bracketing,
                    int midrule_rhs_index, char dollar_or_at,
-                   unsigned indent)
+                   int indent)
 {
-  for (unsigned i = 0; i < variant_count; ++i)
+  for (int i = 0; i < variant_count; ++i)
     show_sub_message (warning | silent,
                       cp, explicit_bracketing,
                       midrule_rhs_index, dollar_or_at,
@@ -437,7 +437,7 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
 
   /* Add all relevant variants. */
   {
-    unsigned symbol_index;
+    int symbol_index;
     symbol_list *l;
     variant_count = 0;
     for (symbol_index = 0, l = rule; !symbol_list_null (l);
@@ -459,12 +459,12 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
   }
 
   /* Check errors. */
-  unsigned valid_variants = 0;
-  unsigned valid_variant_index = 0;
-  for (unsigned i = 0; i < variant_count; ++i)
+  int valid_variants = 0;
+  int valid_variant_index = 0;
+  for (int i = 0; i < variant_count; ++i)
     {
       variant *var = &variant_table[i];
-      unsigned symbol_index = var->symbol_index;
+      int symbol_index = var->symbol_index;
 
       /* Check visibility from midrule actions. */
       if (midrule_rhs_index != 0
@@ -490,9 +490,9 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
     {
     case 0:
       {
-        unsigned len = (explicit_bracketing || !ref_tail_fields) ?
+        int len = (explicit_bracketing || !ref_tail_fields) ?
           cp_end - cp : ref_tail_fields - cp;
-        unsigned indent = 0;
+        int indent = 0;
 
         complain_indent (text_loc, complaint, &indent,
                          _("invalid reference: %s"), quote (text));
@@ -525,7 +525,7 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
       }
     case 1:
       {
-        unsigned indent = 0;
+        int indent = 0;
         if (variant_count > 1)
           {
             complain_indent (text_loc, Wother, &indent,
@@ -535,7 +535,7 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
                                dollar_or_at, indent + SUB_INDENT);
           }
         {
-          unsigned symbol_index =
+          int symbol_index =
             variant_table[valid_variant_index].symbol_index;
           return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
         }
@@ -543,7 +543,7 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
     case 2:
     default:
       {
-        unsigned indent = 0;
+        int indent = 0;
         complain_indent (text_loc, complaint, &indent,
                          _("ambiguous reference: %s"), quote (text));
         show_sub_messages (complaint,
diff --git a/src/scan-gram.l b/src/scan-gram.l
index 43d16de2..861a58cb 100644
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -97,7 +97,7 @@ gram_scanner_last_string_free (void)
 }
 
 static void handle_syncline (char *, location);
-static unsigned long scan_integer (char const *p, int base, location loc);
+static int scan_integer (char const *p, int base, location loc);
 static int convert_ucn_to_byte (char const *hex_text);
 static void unexpected_eof (boundary, char const *);
 static void unexpected_newline (boundary, char const *);
@@ -600,22 +600,22 @@ eqopt    ({sp}=)?
 {
   \\[0-7]{1,3} {
     verify (UCHAR_MAX < ULONG_MAX);
-    unsigned long c = strtoul (yytext + 1, NULL, 8);
-    if (!c || UCHAR_MAX < c)
+    long c = strtol (yytext + 1, NULL, 8);
+    if (0 < c && c <= UCHAR_MAX)
+      obstack_1grow (&obstack_for_string, c);
+    else
       complain (loc, complaint, _("invalid number after \\-escape: %s"),
                 yytext+1);
-    else
-      obstack_1grow (&obstack_for_string, c);
   }
 
   \\x[0-9abcdefABCDEF]+ {
     verify (UCHAR_MAX < ULONG_MAX);
-    unsigned long c = strtoul (yytext + 2, NULL, 16);
-    if (!c || UCHAR_MAX < c)
+    long c = strtol (yytext + 2, NULL, 16);
+    if (0 < c && c <= UCHAR_MAX)
+      obstack_1grow (&obstack_for_string, c);
+    else
       complain (loc, complaint, _("invalid number after \\-escape: %s"),
                 yytext+1);
-    else
-      obstack_1grow (&obstack_for_string, c);
   }
 
   \\a   obstack_1grow (&obstack_for_string, '\a');
@@ -810,7 +810,7 @@ eqopt    ({sp}=)?
 | Scan NUMBER for a base-BASE integer at location LOC.  |
 `------------------------------------------------------*/
 
-static unsigned long
+static int
 scan_integer (char const *number, int base, location loc)
 {
   verify (INT_MAX < ULONG_MAX);
@@ -818,9 +818,9 @@ scan_integer (char const *number, int base, location loc)
     complain (&loc, Wyacc,
               _("POSIX Yacc does not support hexadecimal literals"));
 
-  unsigned long num = strtoul (number, NULL, base);
+  long num = strtol (number, NULL, base);
 
-  if (INT_MAX < num)
+  if (! (0 <= num && num <= INT_MAX))
     {
       complain (&loc, complaint, _("integer out of range: %s"),
                 quote (number));
@@ -841,7 +841,7 @@ static int
 convert_ucn_to_byte (char const *ucn)
 {
   verify (UCHAR_MAX <= INT_MAX);
-  unsigned long code = strtoul (ucn + 2, NULL, 16);
+  long code = strtol (ucn + 2, NULL, 16);
 
   /* FIXME: Currently we assume Unicode-compatible unibyte characters
      on ASCII hosts (i.e., Latin-1 on hosts with 8-bit bytes).  On
@@ -849,7 +849,7 @@ convert_ucn_to_byte (char const *ucn)
      These limitations should be removed once we add support for
      multibyte characters.  */
 
-  if (UCHAR_MAX < code)
+  if (! (0 <= code && code <= UCHAR_MAX))
     return -1;
 
 #if ! ('$' == 0x24 && '@' == 0x40 && '`' == 0x60 && '~' == 0x7e)
@@ -896,8 +896,8 @@ static void
 handle_syncline (char *args, location loc)
 {
   char *file;
-  unsigned long lineno = strtoul (args, &file, 10);
-  if (INT_MAX <= lineno)
+  long lineno = strtol (args, &file, 10);
+  if (! (0 <= lineno && lineno <= INT_MAX))
     {
       complain (&loc, Wother, _("line number overflow"));
       lineno = INT_MAX;
diff --git a/src/scan-skel.l b/src/scan-skel.l
index 487e9f5d..0303b494 100644
--- a/src/scan-skel.l
+++ b/src/scan-skel.l
@@ -209,7 +209,7 @@ at_basename (int argc, char *argv[], char **out_namep, int *out_linenop)
 static void
 at_complain (int argc, char *argv[], char **out_namep, int *out_linenop)
 {
-  static unsigned indent;
+  static int indent;
   warnings w = flag (argv[1]);
   location loc;
   location *locp = NULL;
diff --git a/src/symtab.c b/src/symtab.c
index 66a99059..90884ad5 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -279,7 +279,7 @@ static void
 complain_symbol_redeclared (symbol *s, const char *what, location first,
                             location second)
 {
-  unsigned i = 0;
+  int i = 0;
   locations_sort (&first, &second);
   complain_indent (&second, complaint, &i,
                    _("%s redeclaration for %s"), what, s->tag);
@@ -292,7 +292,7 @@ static void
 complain_semantic_type_redeclared (semantic_type *s, const char *what, location first,
                                    location second)
 {
-  unsigned i = 0;
+  int i = 0;
   locations_sort (&first, &second);
   complain_indent (&second, complaint, &i,
                    _("%s redeclaration for <%s>"), what, s->tag);
@@ -304,7 +304,7 @@ complain_semantic_type_redeclared (semantic_type *s, const char *what, location
 static void
 complain_class_redeclared (symbol *sym, symbol_class class, location second)
 {
-  unsigned i = 0;
+  int i = 0;
   complain_indent (&second, complaint, &i,
                    class == token_sym
                    ? _("symbol %s redeclared as a token")
@@ -463,7 +463,7 @@ symbol_class_set (symbol *sym, symbol_class class, location loc, bool declaring)
         {
           if (s->status == declared)
             {
-              unsigned i = 0;
+              int i = 0;
               complain_indent (&loc, Wother, &i,
                                _("symbol %s redeclared"), sym->tag);
               i += SUB_INDENT;
@@ -668,7 +668,7 @@ symbol_pack_processor (void *this, void *null ATTRIBUTE_UNUSED)
 static void
 complain_user_token_number_redeclared (int num, symbol *first, symbol *second)
 {
-  unsigned i = 0;
+  int i = 0;
   symbols_sort (&first, &second);
   complain_indent (&second->location, complaint, &i,
                    _("user token number %d redeclaration for %s"),
diff --git a/src/tables.c b/src/tables.c
index 39434e77..ec89b3ed 100644
--- a/src/tables.c
+++ b/src/tables.c
@@ -84,7 +84,7 @@ int nvectors;
 
 static base_number **froms;
 static base_number **tos;
-static unsigned **conflict_tos;
+static int **conflict_tos;
 static size_t *tally;
 static base_number *width;
 
@@ -115,9 +115,9 @@ base_number base_ninf = 0;
    -nstates..table_size (as an upper bound) */
 static bitset pos_set = NULL;
 
-static unsigned *conflrow;
-unsigned *conflict_table;
-unsigned *conflict_list;
+static int *conflrow;
+int *conflict_table;
+int *conflict_list;
 int conflict_list_cnt;
 static int conflict_list_free;
 
@@ -391,7 +391,7 @@ save_row (state_number s)
       /* Allocate non defaulted actions.  */
       base_number *sp1 = froms[s] = xnmalloc (count, sizeof *sp1);
       base_number *sp2 = tos[s] = xnmalloc (count, sizeof *sp2);
-      unsigned *sp3 = conflict_tos[s] =
+      int *sp3 = conflict_tos[s] =
         nondeterministic_parser ? xnmalloc (count, sizeof *sp3) : NULL;
 
       /* Store non defaulted actions.  */
@@ -646,7 +646,7 @@ pack_vector (vector_number vector)
   size_t t = tally[i];
   base_number *from = froms[i];
   base_number *to = tos[i];
-  unsigned *conflict_to = conflict_tos[i];
+  int *conflict_to = conflict_tos[i];
 
   aver (t != 0);
 
diff --git a/src/tables.h b/src/tables.h
index 0504e38c..fe12952e 100644
--- a/src/tables.h
+++ b/src/tables.h
@@ -122,8 +122,8 @@ extern base_number *base;
    keep parser tables small.  */
 extern base_number base_ninf;
 
-extern unsigned *conflict_table;
-extern unsigned *conflict_list;
+extern int *conflict_table;
+extern int *conflict_list;
 extern int conflict_list_cnt;
 
 extern base_number *table;