proc.c: fix infinite loop

* proc.c (rb_proc_get_iseq): proc made from symbol does not have
  iseq.  fix infinite loop.  [ruby-core:72381] [Bug #11845]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53206 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,13 @@
+Sun Dec 20 00:29:00 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* proc.c (rb_proc_get_iseq): proc made from symbol does not have
+	  iseq.  fix infinite loop.  [ruby-core:72381] [Bug #11845]
+
+Sun Dec 20 00:28:51 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* proc.c (rb_proc_get_iseq): proc made from symbol does not have
+	  iseq.  fix infinite loop.  [ruby-core:72381] [Bug #11845]
+
 Sat Dec 19 20:06:10 2015  Naohisa Goto  <ngotogenome@gmail.com>
 
 	* enc/windows_1250.c: Should not use C++ style comments (C99 feature).

proc.c

@@ -975,7 +975,6 @@ rb_proc_get_iseq(VALUE self, int *is_proc)
     const rb_proc_t *proc;
     const rb_iseq_t *iseq;
 
-  again:
     GetProcPtr(self, proc);
     iseq = proc->block.iseq;
     if (is_proc) *is_proc = !proc->is_lambda;
@@ -990,8 +989,7 @@ rb_proc_get_iseq(VALUE self, int *is_proc)
 	return iseq;
     }
     else if (SYMBOL_P(iseq)) {
-	self = rb_sym_to_proc((VALUE)iseq);
-	goto again;
+	return NULL;
     }
     else {
 	return rb_iseq_check(iseq);

test/ruby/test_symbol.rb

@@ -164,6 +164,18 @@ class TestSymbol < Test::Unit::TestCase
     end;
   end
 
+  def test_to_proc_iseq
+    assert_separately([], <<~"end;", timeout: 1) # do
+      bug11845 = '[ruby-core:72381] [Bug #11845]'
+      assert_nil(:class.to_proc.source_location, bug11845)
+      assert_equal([[:rest]], :class.to_proc.parameters, bug11845)
+      c = Class.new {define_method(:klass, :class.to_proc)}
+      m = c.instance_method(:klass)
+      assert_nil(m.source_location, bug11845)
+      assert_equal([[:rest]], m.parameters, bug11845)
+    end;
+  end
+
   def test_call
     o = Object.new
     def o.foo(x, y); x + y; end