--- flexmock-2.3.6/test/test_helper.rb.ruby3	2021-01-24 00:41:42.121385766 +0900
+++ flexmock-2.3.6/test/test_helper.rb	2021-01-24 00:44:25.866236105 +0900
@@ -50,7 +50,7 @@
     # added.
     def assert_mock_failure(klass, options={}, &block)
       ex = assert_failure(klass, options, &block)
-      file = eval("__FILE__", block.binding)
+      file = block.binding.source_location.first
       assert_matching_line(ex, file, options)
     end