Distinguish pre-condition and post-condition loops

ast.c

@@ -374,7 +374,8 @@ node_children(rb_ast_t *ast, NODE *node)
         goto loop;
       case NODE_UNTIL:
       loop:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_cond, node->nd_body);
+        return rb_ary_push(rb_ary_new_from_node_args(ast, 2, node->nd_cond, node->nd_body),
+                           (node->nd_state ? Qtrue : Qfalse));
       case NODE_ITER:
       case NODE_FOR:
         return rb_ary_new_from_node_args(ast, 2, node->nd_iter, node->nd_body);

test/ruby/test_ast.rb

@@ -278,4 +278,16 @@ class TestAst < Test::Unit::TestCase
     assert_equal(:LIT, body.type)
     assert_equal([1], body.children)
   end
+
+  def test_while
+    node = RubyVM::AbstractSyntaxTree.parse('1 while 1')
+    _, _, body = *node.children
+    assert_equal(:WHILE, body.type)
+    type1 = body.children[2]
+    node = RubyVM::AbstractSyntaxTree.parse('begin 1 end while 1')
+    _, _, body = *node.children
+    assert_equal(:WHILE, body.type)
+    type2 = body.children[2]
+    assert_not_equal(type1, type2)
+  end
 end