merge revision(s) cd4f5b13228879d954fa97b6aa479c4a5ef4fb0a,8db269edb3550a85dfab9b193ea115ca36912ced,ab63f6d8543903f177c46634f38e5428655f003b: [Backport #18140]

	Guard array when appending

	This prevents early collection of the array.  The GC doesn't see the
	array on the stack when Ruby is compiled with optimizations enabled

	[ruby-core:105099] [Bug #18140]
	---
	 array.c                 | 1 +
	 test/ruby/test_array.rb | 6 ++++++
	 2 files changed, 7 insertions(+)

	Guard array when appending

	This prevents early collection of the array.  The GC doesn't see the
	array on the stack when Ruby is compiled with optimizations enabled

	Thanks @jhaberman for the test case

	[ruby-core:105099] [Bug #18140]
	---
	 ext/-test-/array/concat/depend          | 321 ++++++++++++++++++++++++++++++++
	 ext/-test-/array/concat/extconf.rb      |   2 +
	 ext/-test-/array/concat/to_ary_conact.c |  64 +++++++
	 test/-ext-/array/test_to_ary_concat.rb  |  20 ++
	 4 files changed, 407 insertions(+)
	 create mode 100644 ext/-test-/array/concat/depend
	 create mode 100644 ext/-test-/array/concat/extconf.rb
	 create mode 100644 ext/-test-/array/concat/to_ary_conact.c
	 create mode 100644 test/-ext-/array/test_to_ary_concat.rb

	Refined test [Bug #18140]

	---
	 ext/-test-/array/concat/to_ary_conact.c | 48 +++++++--------------------------
	 test/ruby/test_array.rb                 |  5 +++-
	 2 files changed, 13 insertions(+), 40 deletions(-)

1 files changed, 1 insertions, 0 deletions

diff --git a/array.c b/array.c
index 7ed3b14ef5..6993796854 100644
--- a/array.c
+++ b/array.c
@@ -4821,6 +4821,7 @@ ary_append(VALUE x, VALUE y)
     if (n > 0) {
         rb_ary_splice(x, RARRAY_LEN(x), 0, RARRAY_CONST_PTR_TRANSIENT(y), n);
     }
+    RB_GC_GUARD(y);
     return x;
 }