Don't modify rest array when using ruby2_keywords

Previously, the rest array was modified, but it turns out that is
not necessary.  Not modifying the rest array fixes cases when the
rest array is used more than once.

2 files changed, 10 insertions, 2 deletions

diff --git a/test/ruby/test_keyword.rb b/test/ruby/test_keyword.rb
index bbb107dedd..29335a4963 100644
--- a/test/ruby/test_keyword.rb
+++ b/test/ruby/test_keyword.rb
@@ -2649,6 +2649,11 @@ class TestKeywordArguments < Test::Unit::TestCase
         baz(*args)
       end
 
+      ruby2_keywords def foo_baz2(*args)
+        baz(*args)
+        baz(*args)
+      end
+
       ruby2_keywords def foo_foo_bar(meth, *args)
         foo_bar(meth, *args)
       end
@@ -2761,6 +2766,10 @@ class TestKeywordArguments < Test::Unit::TestCase
     h1 = {a: 1}
     o = c.new
 
+    assert_equal([1, h1], o.foo_baz2(1, :a=>1))
+    assert_equal([1], o.foo_baz2(1, **{}))
+    assert_equal([h1], o.foo_baz2(h1, **{}))
+
     assert_equal([[1], h1], o.foo(:bar, 1, :a=>1))
     assert_equal([1, h1], o.foo(:baz, 1, :a=>1))
     assert_equal([[1], h1], o.bfoo(:bar, 1, :a=>1))
diff --git a/vm_args.c b/vm_args.c
index 78a0f0dfbe..6729d54af7 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -742,7 +742,6 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
             if (RB_TYPE_P(rest_last, T_HASH) &&
                 (((struct RHash *)rest_last)->basic.flags & RHASH_PASS_AS_KEYWORDS)) {
                 rest_last = rb_hash_dup(rest_last);
-                RARRAY_ASET(args->rest, len - 1, rest_last);
                 kw_flag |= VM_CALL_KW_SPLAT;
                 if (iseq->body->param.flags.ruby2_keywords) {
                     remove_empty_keyword_hash = 0;
@@ -754,7 +753,7 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
         }
 
         if (kw_flag & VM_CALL_KW_SPLAT) {
-            if (len > 0 && ignore_keyword_hash_p(RARRAY_AREF(args->rest, len - 1), iseq)) {
+            if (len > 0 && ignore_keyword_hash_p(rest_last, iseq)) {
                 if (given_argc != min_argc) {
                     if (remove_empty_keyword_hash) {
                         arg_rest_dup(args);