( cont. )

imo the more usual concern would be mistakenly removing code that was not dead.

Without a design document, we might think there would be no senders of #factorial without understanding that the intention was to invoke that method on the command line.

For example,

    $ cat fact.st
    Stdio stdout 
        nextPutAll: 100 factorial printString; 
        nextPut: Character lf.!
    SmalltalkImage current snapshot: false andQuit: true!

    $ bin/pharo --headless Pharo10-SNAPSHOT-64bit-502addc.image fact.st
    93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000

So instrumenting methods and logging — https://stackoverflow.com/a/162719