Environment Information

• JRuby version (jruby -v): jruby 9.2.14.0 (2.5.7) 2020-12-08 ebe64bafb9 Java HotSpot(TM) 64-Bit Server VM 25.45-b02 on 1.8.0_45-b14 +jit [darwin-x86_64]
• Operating system and platform: initially discovered on MacOS 10.13.6, but replicated on Travis under Ubuntu 18.04.5 LTS (Bionic), see below
• Application/framework version: Rails 6.1.2.1
• Code available at: https://github.com/sosol/sosol/tree/rails-6.1.2.1

Expected Behavior

• Dynamic Rails finder methods e.g. find_by_custom_model_attribute() should continue to work

Actual Behavior

• Dynamic Rails finder methods result in Java::JavaLang::ClassCastException: org.jruby.ir.operands.TemporaryClosureVariable cannot be cast to org.jruby.ir.operands.DepthCloneable (full backtrace from Travis under OpenJDK 8 attached here)

I was able to isolate this down to dynamic finders by running a single test and adding debug logging until I could pin it down. With e.g. this change to use where instead, the single test I chose passes instead of resulting in Java::JavaLang::ClassCastException (single test invoked with rails test test/unit/publication_test.rb:91).

Exception occurs on both Rails 6.1.2.1 and Rails 6.1.2.

Exception does not occur under Rails 6.1.1 with nothing else changed: https://travis-ci.com/github/sosol/sosol/builds/217275737

I also expanded tests from OpenJDK 8 up through OpenJDK 15 to verify that it's not related to the older JVM with Rails 6.1.2.1: https://travis-ci.com/github/sosol/sosol/builds/217273487

Only difference between the two is the Rails version (+ dependencies): sosol/sosol@rails-6.1.2.1...rails-6.1.1

Please let me know if you think I should file a regression on Rails or whichever action/active* gem change is responsible instead of or in addition to here.