Issue #20966 has been updated by ufuk (Ufuk Kayserilioglu). I think you are being tripped up by the low precedence of the unary operator, which is applied after the whole chain of calls are made. Try parenthesizing the unary plus and the string. ---------------------------------------- Bug #20966: Unary plus String warns about freezing https://bugs.ruby-lang.org/issues/20966#change-111072 * Author: getajobmike (Mike Perham) * Status: Open * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- ``` /Users/mperham/src/sidekiq/test/profiling_test.rb:49: warning: literal string will be frozen in the future (run with --debug-frozen-string-literal for more information) ``` -- https://bugs.ruby-lang.org/