vm_eval.c: Symbol#to_proc and instance_exec

* vm_eval.c (yield_under): should evaluate the proc on the first
  argument.  [ruby-core:78839] [Bug #13074]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57194 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_symbol.rb

@@ -201,6 +201,12 @@ class TestSymbol < Test::Unit::TestCase
     end;
   end
 
+  def test_to_proc_instance_exec
+    bug = '[ruby-core:78839] [Bug #13074] should evaluate on the argument'
+    assert_equal(2, BasicObject.new.instance_exec(1, &:succ), bug)
+    assert_equal(3, BasicObject.new.instance_exec(1, 2, &:+), bug)
+  end
+
   def test_call
     o = Object.new
     def o.foo(x, y); x + y; end

vm_eval.c

@@ -1591,7 +1591,8 @@ yield_under(VALUE under, VALUE self, int argc, const VALUE *argv)
 	    block_handler = vm_proc_to_block_handler(VM_BH_TO_PROC(block_handler));
 	    goto again;
 	  case block_handler_type_symbol:
-	    return rb_sym_proc_call(SYM2ID(VM_BH_TO_SYMBOL(block_handler)), 1, &self, VM_BLOCK_HANDLER_NONE);
+	    return rb_sym_proc_call(SYM2ID(VM_BH_TO_SYMBOL(block_handler)),
+				    argc, argv, VM_BLOCK_HANDLER_NONE);
 	}
 
 	new_captured.self = self;