[Feature #20205] The warning now suggests running with --debug-frozen-string-literal: ``` test.rb:3: warning: literal string will be frozen in the future (run with --debug-frozen-string-literal for more information) ``` When using --debug-frozen-string-literal, the location where the string was created is shown: ``` test.rb:3: warning: literal string will be frozen in the future test.rb:1: info: the string was created here ``` When resurrecting strings and debug mode is not enabled, the overhead is a simple FL_TEST_RAW. When mutating chilled strings and deprecation warnings are not enabled, the overhead is a simple warning category enabled check. Co-authored-by: Jean Boussier <[email protected]> Co-authored-by: Nobuyoshi Nakada <[email protected]> Co-authored-by: Jean Boussier <[email protected]>