Feature #3446: unused variable warning

• Status: Closed
• Assignee: -
• Target version: -

[nobu (Nobuyoshi Nakada)]

=begin
なかだです。

http://d.hatena.ne.jp/kwatch/20100616/1276650107 にある、未使用
変数に対する警告を実装してみました。

diff --git i/parse.y w/parse.y
index ebe9fef..8dbbacf 100644
--- i/parse.y
+++ w/parse.y
@@ -99,6 +99,7 @@ struct vtable {
struct local_vars {
struct vtable *args;
struct vtable *vars;

• struct vtable *used;
  struct local_vars *prev;
  };

@@ -167,7 +168,7 @@ vtable_included(const struct vtable * tbl, ID id)
if (POINTER_P(tbl)) {
for (i = 0; i < tbl->pos; i++) {
if (tbl->tbl[i] == id) {

•            return 1;
  

•            return i+1;
         }
     }
  

  }
  @@ -8916,6 +8917,27 @@ new_args_gen(struct parser_params *parser, NODE *m, NODE *o, ID r, NODE *p, ID b
  ruby_sourceline = saved_line;
  return node;
  }

+#define LVAR_USED (1UL << (sizeof(ID) * CHAR_BIT - 1))
+
+static void
+warn_unused_var(struct parser_params *parser, struct local_vars *local)
+{

• int i, cnt;
• ID *v, *u;
• if (!local->used) return;
• v = local->vars->tbl;
• u = local->used->tbl;
• cnt = local->used->pos;
• if (cnt != local->vars->pos) {
• rb_bug("local->used->pos != local->vars->pos");
• }
• for (i = 0; i < cnt; ++i) {
• if (!v[i] || (u[i] & LVAR_USED)) continue;
• rb_compile_warn(ruby_sourcefile, (int)u[i], "assigned but unused variable %s", rb_id2name(v[i]));
• }
  +}
  #endif /* !RIPPER */

static void
@@ -8927,6 +8949,7 @@ local_push_gen(struct parser_params *parser, int inherit_dvars)
local->prev = lvtbl;
local->args = vtable_alloc(0);
local->vars = vtable_alloc(inherit_dvars ? DVARS_INHERIT : DVARS_TOPSCOPE);

• local->used = RTEST(ruby_verbose) ? vtable_alloc(0) : 0;
  lvtbl = local;
  }

@@ -8934,6 +8957,10 @@ static void
local_pop_gen(struct parser_params *parser)
{
struct local_vars *local = lvtbl->prev;

• if (lvtbl->used) {
• warn_unused_var(parser, lvtbl);
• vtable_free(lvtbl->used);
• }
  vtable_free(lvtbl->args);
  vtable_free(lvtbl->vars);
  xfree(lvtbl);
  @@ -8982,28 +9009,37 @@ static int
  local_var_gen(struct parser_params *parser, ID id)
  {
  vtable_add(lvtbl->vars, id);
• if (lvtbl->used) {
• vtable_add(lvtbl->used, (ID)ruby_sourceline);
• }
  return vtable_size(lvtbl->vars) - 1;
  }

static int
local_id_gen(struct parser_params *parser, ID id)
{

• struct vtable *vars, *args;

• struct vtable *vars, *args, *used;

  vars = lvtbl->vars;
  args = lvtbl->args;

• used = lvtbl->used;

  while (vars && POINTER_P(vars->prev)) {
  vars = vars->prev;
  args = args->prev;

• if (used) used = used->prev;
  }

  if (vars && vars->prev == DVARS_INHERIT) {
  return rb_local_defined(id);
  }

• else if (vtable_included(args, id)) {

• return 1;

• }
  else {

• return (vtable_included(args, id) ||

•  vtable_included(vars, id));
  

• int i = vtable_included(vars, id);
• if (i && used) used->tbl[i-1] |= LVAR_USED;
• return i != 0;
  }
  }

@@ -9012,6 +9048,9 @@ dyna_push_gen(struct parser_params *parser)
{
lvtbl->args = vtable_alloc(lvtbl->args);
lvtbl->vars = vtable_alloc(lvtbl->vars);

• if (lvtbl->used) {
• lvtbl->used = vtable_alloc(lvtbl->used);
• }
  return lvtbl->args;
  }

@@ -9020,6 +9059,11 @@ dyna_pop_1(struct parser_params *parser)
{
struct vtable *tmp;

• if ((tmp = lvtbl->used) != 0) {
• warn_unused_var(parser, lvtbl);
• lvtbl->used = lvtbl->used->prev;
• vtable_free(tmp);
• }
  tmp = lvtbl->args;
  lvtbl->args = lvtbl->args->prev;
  vtable_free(tmp);
  @@ -9051,20 +9095,24 @@ dyna_in_block_gen(struct parser_params *parser)
  static int
  dvar_defined_gen(struct parser_params *parser, ID id)
  {

• struct vtable *vars, *args;

• struct vtable *vars, *args, *used;

• int i;

  args = lvtbl->args;
  vars = lvtbl->vars;

• used = lvtbl->used;

  while (POINTER_P(vars)) {
  if (vtable_included(args, id)) {
  return 1;
  }

• if (vtable_included(vars, id)) {

• if ((i = vtable_included(vars, id)) != 0) {

•  if (used) used->tbl[i-1] |= LVAR_USED;
   return 1;
  

  }
  args = args->prev;
  vars = vars->prev;

• if (used) used = used->prev;
  }

  if (vars == DVARS_INHERIT) {
  diff --git i/test/ruby/test_rubyoptions.rb w/test/ruby/test_rubyoptions.rb
  index 683677c..0d70357 100644
  --- i/test/ruby/test_rubyoptions.rb
  +++ w/test/ruby/test_rubyoptions.rb
  @@ -415,4 +415,9 @@ class TestRubyOptions < Test::Unit::TestCase
  ensure
  t.close(true) if t
  end

• def test_unused_variable

• assert_in_out_err(["-we", "a=1"], "", [], ["-e:1: warning: assigned but unused variable a"])

• assert_in_out_err(["-we", "1.times do\n a=1\nend"], "", [], ["-e:2: warning: assigned but unused variable a"])

• end
  end
  

--
--- 僕の前にBugはない。
--- 僕の後ろにBugはできる。
中田 伸悦
=end

[matz (Yukihiro Matsumoto)]

=begin
まつもと ゆきひろです

In message "Re: [ruby-dev:41620] [Feature:trunk] unused variable warning"
on Wed, 16 Jun 2010 17:44:02 +0900, Nobuyoshi Nakada [e-mail] writes:

|http://d.hatena.ne.jp/kwatch/20100616/1276650107 にある、未使用
|変数に対する警告を実装してみました。

コミットしてくださいませんか。

=end

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

=begin
This issue was solved with changeset r28339.
Nobuyoshi, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

=end