* enumerator.c: Fix state handling for Lazy#drop

[bug #7696] [bug #7691]

* test/ruby/test_lazy_enumerator.rb: test for above

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38922 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

enumerator.c

@@ -1725,13 +1725,16 @@ lazy_drop_size(VALUE lazy)
 static VALUE
 lazy_drop_func(VALUE val, VALUE args, int argc, VALUE *argv)
 {
-    NODE *memo = RNODE(args);
-
-    if (memo->u3.cnt == 0) {
+    long remain;
+    VALUE memo = rb_ivar_get(argv[0], id_memo);
+    if (NIL_P(memo)) {
+	memo = args;
+    }
+    if ((remain = NUM2LONG(memo)) == 0) {
 	rb_funcall2(argv[0], id_yield, argc - 1, argv + 1);
     }
     else {
-	memo->u3.cnt--;
+	rb_ivar_set(argv[0], id_memo, LONG2NUM(--remain));
     }
     return Qnil;
 }
@@ -1739,15 +1742,13 @@ lazy_drop_func(VALUE val, VALUE args, int argc, VALUE *argv)
 static VALUE
 lazy_drop(VALUE obj, VALUE n)
 {
-    NODE *memo;
     long len = NUM2LONG(n);
 
     if (len < 0) {
 	rb_raise(rb_eArgError, "attempt to drop negative size");
     }
-    memo = NEW_MEMO(0, 0, len);
     return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
-					 lazy_drop_func, (VALUE) memo),
+					 lazy_drop_func, n),
 			   rb_ary_new3(1, n), lazy_drop_size);
 }
 

test/ruby/test_lazy_enumerator.rb

@@ -257,6 +257,13 @@ class TestLazyEnumerator < Test::Unit::TestCase
     assert_equal([*(6..10)]*5, drop5.flat_map{drop5}.force, bug7696)
   end
 
+  def test_drop_nested
+    bug7696 = '[ruby-core:51470]'
+    a = Step.new(1..10)
+    drop5 = a.lazy.drop(5)
+    assert_equal([*(6..10)]*5, drop5.flat_map{drop5}.force, bug7696)
+  end
+
   def test_take_rewound
     bug7696 = '[ruby-core:51470]'
     e=(1..42).lazy.take(2)