diff --git a/lib/irb/source_finder.rb b/lib/irb/source_finder.rb
index 5d7d729d1..c515da570 100644
--- a/lib/irb/source_finder.rb
+++ b/lib/irb/source_finder.rb
@@ -100,7 +100,7 @@ def find_source(signature, super_level = 0)
         Source.new(file, line)
       elsif method
         # Method defined with eval, probably in IRB session
-        source = RubyVM::AbstractSyntaxTree.of(method)&.source rescue nil
+        source = RubyVM::InstructionSequence.of(method)&.script_lines&.join rescue nil
         Source.new(file, line, source)
       end
     rescue EvaluationError