YJIT: Add regression test for local type tracking

The test in [1] was removed because it stopped working when we limited
the power of Kernel#binding in [2]. However, the underlying issue could
still be reproduced using blocks. Add back a regression test.

I tested the test by commenting out the fix from [1].

[1]: 54c91042ed61a869d4a66fc089b21f56d165265f
[2]: 343ea9967e4a6b279eed6bd8e81ad0bdc747f254

1 files changed, 20 insertions, 0 deletions

diff --git a/bootstraptest/test_yjit.rb b/bootstraptest/test_yjit.rb
index 09bce6735b..ea564a6a6e 100644
--- a/bootstraptest/test_yjit.rb
+++ b/bootstraptest/test_yjit.rb
@@ -1,3 +1,23 @@
+assert_equal 'true', %q{
+  # regression test for tracking type of locals for too long
+  def local_setting_cmp(five)
+    victim = 5
+    five.define_singleton_method(:respond_to?) do |_, _|
+      victim = nil
+    end
+
+    # +1 makes YJIT track that victim is a number and
+    # defined? calls respond_to? from above indirectly
+    unless (victim + 1) && defined?(five.something)
+      # Would return wrong result if we still think `five` is a number
+      victim.nil?
+    end
+  end
+
+  local_setting_cmp(Object.new)
+  local_setting_cmp(Object.new)
+}
+
 assert_equal '18374962167983112447', %q{
   # regression test for incorrectly discarding 32 bits of a pointer when it
   # comes to default values.