YJIT: Implement VM_CALL_ARGS_BLOCKARG with Proc for ISeq calls

Rack uses this. Speculate that the `obj` in `the_call(&obj)`
will be a proc when the compile-time sample is a proc.

Co-authored-by: Takashi Kokubun <takashikkbn@gmail.com>
Co-authored-by: Maxime Chevalier-Boisvert <maxime.chevalierboisvert@shopify.com>
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/test_yjit.rb b/test/ruby/test_yjit.rb
index 0207f4aaf1..5347028550 100644
--- a/test/ruby/test_yjit.rb
+++ b/test/ruby/test_yjit.rb
@@ -1320,6 +1320,16 @@ class TestYJIT < Test::Unit::TestCase
     RUBY
   end
 
+  def test_proc_block_arg
+    assert_compiles(<<~RUBY, result: [:proc, :no_block])
+      def yield_if_given = block_given? ? yield : :no_block
+
+      def call(block_arg = nil) = yield_if_given(&block_arg)
+
+      [call(-> { :proc }), call]
+    RUBY
+  end
+
   private
 
   def code_gc_helpers