diff --git a/ChangeLog b/ChangeLog
index dba4754514..558a19b9cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Tue Aug 04 15:30:04 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* proc.c (rb_block_clear_env_self): clear by Qfalse intead of Qnil.
+	  [Bug #11409]
+
+	* test/ruby/test_eval.rb: add tests for this issue,
+	  written by @0x0dea.
+	  https://github.com/ruby/ruby/pull/988
+
 Tue Aug  4 12:12:14 2015  Eric Wong  <e@80x24.org>
 
 	* variable.c: wrap long lines
diff --git a/proc.c b/proc.c
index 2eb46ad5d2..4b67c69755 100644
--- a/proc.c
+++ b/proc.c
@@ -670,7 +670,7 @@ rb_block_clear_env_self(VALUE proc)
     rb_env_t *env;
     GetProcPtr(proc, po);
     GetEnvPtr(rb_vm_proc_envval(po), env);
-    env->env[0] = Qnil;
+    env->env[0] = Qfalse;
     return proc;
 }
 
diff --git a/test/ruby/test_eval.rb b/test/ruby/test_eval.rb
index 9d8db3017b..02dbb9b379 100644
--- a/test/ruby/test_eval.rb
+++ b/test/ruby/test_eval.rb
@@ -126,6 +126,10 @@ class TestEval < Test::Unit::TestCase
     }
   end
 
+  def test_module_eval_block_symbol
+    assert_equal "Math", Math.module_eval(&:to_s)
+  end
+
   def forall_TYPE
     objects = [Object.new, [], nil, true, false] # TODO: check
     objects.each do |obj|
@@ -199,6 +203,12 @@ class TestEval < Test::Unit::TestCase
     assert_equal self, pr.call
   end
 
+  def test_instance_eval_block_symbol
+    forall_TYPE do |o|
+      assert_equal o.to_s, o.instance_eval(&:to_s)
+    end
+  end
+
   def test_instance_eval_cvar
     [Object.new, [], 7, :sym, true, false, nil].each do |obj|
       assert_equal(13, obj.instance_eval("@@cvar"))