* parse.y (shadowing_lvar_gen): get rid of adding extra name for

  shadowing local variable.  [ruby-dev:41628]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@28364 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 76 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 7179f3f806..ff18c20005 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Jun 20 14:40:50 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (shadowing_lvar_gen): get rid of adding extra name for
+	  shadowing local variable.  [ruby-dev:41628]
+
 Sat Jun 19 11:11:37 2010  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* lib/irb.rb: remove double exclamation marks.  a patch from Diego
@@ -75,6 +80,15 @@ Thu Jun 17 18:37:47 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
 	* transcode.c (rb_str_encode): should return new string always.
 	  fixed #3444.
 
+Wed Jun 16 18:34:54 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* parse.y: ripper needs warn_unused_var(), too.
+
+Wed Jun 16 18:20:00 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (warn_unused_var): warn unused variables.
+	  [ruby-dev:41620]
+
 Wed Jun 16 15:40:53 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* error.c (rb_bug): existence of _set_abort_behavior() depends on
diff --git a/parse.y b/parse.y
index ebe9fef233..2b8bd7ecf9 100644
--- a/parse.y
+++ b/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;
             }
         }
     }
@@ -8238,7 +8239,6 @@ shadowing_lvar_gen(struct parser_params *parser, ID name)
 	}
 	else if (dvar_defined(name) || local_id(name)) {
 	    rb_warningS("shadowing outer local variable - %s", rb_id2name(name));
-	    vtable_add(lvtbl->vars, name);
 	}
     }
     else {
@@ -8918,6 +8918,27 @@ new_args_gen(struct parser_params *parser, NODE *m, NODE *o, ID r, NODE *p, ID b
 }
 #endif /* !RIPPER */
 
+#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]));
+    }
+}
+
 static void
 local_push_gen(struct parser_params *parser, int inherit_dvars)
 {
@@ -8927,6 +8948,7 @@ 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 +8956,10 @@ 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 +9008,37 @@ 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 +9047,9 @@ 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 +9058,11 @@ 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 +9094,24 @@ 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 a/test/ruby/test_rubyoptions.rb b/test/ruby/test_rubyoptions.rb
index 683677c160..65e692ecc0 100644
--- a/test/ruby/test_rubyoptions.rb
+++ b/test/ruby/test_rubyoptions.rb
@@ -415,4 +415,10 @@ class TestRubyOptions < Test::Unit::TestCase
   ensure
     t.close(true) if t
   end
+
+  def test_unused_variable
+    feature3446 = '[ruby-dev:41620]'
+    assert_in_out_err(["-we", "a=1"], "", [], ["-e:1: warning: assigned but unused variable - a"], feature3446)
+    assert_in_out_err(["-we", "1.times do\n  a=1\nend"], "", [], ["-e:2: warning: assigned but unused variable - a"], feature3446)
+  end
 end
diff --git a/version.h b/version.h
index b90e4d8cb9..4610505832 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.3"
-#define RUBY_RELEASE_DATE "2010-06-19"
+#define RUBY_RELEASE_DATE "2010-06-20"
 #define RUBY_PATCHLEVEL -1
 #define RUBY_BRANCH_NAME "trunk"
 
@@ -8,7 +8,7 @@
 #define RUBY_VERSION_TEENY 1
 #define RUBY_RELEASE_YEAR 2010
 #define RUBY_RELEASE_MONTH 6
-#define RUBY_RELEASE_DAY 19
+#define RUBY_RELEASE_DAY 20
 
 #include "ruby/version.h"