* vm_args.c (setup_parameters_complex): don't raise ArgumentError

  if an array is given for instance_exec with optional argument.
  [ruby-core:76300] [Bug #12568]
  https://github.com/rails/rails/pull/25699

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55609 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 15 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 687c0d1e28..950d11daf0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Fri Jul  8 03:54:22 2016  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* vm_args.c (setup_parameters_complex): don't raise ArgumentError
+	  if an array is given for instance_exec with optional argument.
+	  [ruby-core:76300] [Bug #12568]
+	  https://github.com/rails/rails/pull/25699
+
 Fri Jul  8 00:47:36 2016  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* vm_eval.c (yield_under): change prototype to get argc/argv.
diff --git a/test/ruby/test_lambda.rb b/test/ruby/test_lambda.rb
index efc3d0f2ca..c65169ac27 100644
--- a/test/ruby/test_lambda.rb
+++ b/test/ruby/test_lambda.rb
@@ -72,6 +72,13 @@ class TestLambdaParameters < Test::Unit::TestCase
     assert_raise(ArgumentError, bug9605) {proc(&plus).call [1,2]}
   end
 
+  def test_instance_exec
+    bug12568 = '[ruby-core:76300] [Bug #12568]'
+    assert_nothing_raised(ArgumentError, bug12568) do
+      instance_exec([1,2,3], &->(a=[]){ a })
+    end
+  end
+
   def yield_1(arg)
     yield arg
   end
diff --git a/vm_args.c b/vm_args.c
index 0f5a3155a2..4917b7f360 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -587,6 +587,7 @@ setup_parameters_complex(rb_thread_t * const th, const rb_iseq_t * const iseq,
       case arg_setup_lambda:
 	if (given_argc == 1 &&
 	    given_argc != iseq->body->param.lead_num &&
+	    !iseq->body->param.flags.has_opt &&
 	    !iseq->body->param.flags.has_rest &&
 	    args_check_block_arg0(args, th)) {
 	    given_argc = RARRAY_LENINT(args->rest);