passed block should keep the lambda-ness

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57243 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/-ext-/iter/test_yield_block.rb

@@ -12,6 +12,12 @@ class TestIter::YieldBlock < Test::Unit::TestCase
     def test(arg, &block)
       block.call(arg) {|blockarg| @blockarg = blockarg}
     end
+    def call_proc(&block)
+      block.call {}
+    end
+    def call_lambda(&block)
+      block.call &->{}
+    end
   end
 
   def test_yield_block
@@ -19,4 +25,10 @@ class TestIter::YieldBlock < Test::Unit::TestCase
     a.yield_block(:test, "foo") {|x, &b| assert_kind_of(Proc, b); b.call(x)}
     assert_equal("foo", a.blockarg)
   end
+
+  def test_yield_lambda
+    a = YieldTest.new
+    assert_not_predicate a.yield_block(:call_proc) {|&b| b}, :lambda?
+    assert_predicate a.yield_block(:call_lambda) {|&b| b}, :lambda?
+  end
 end