Confusingly similar names of the same type

The complete source of quality_similar_bad.ek9, which fails to compile exactly as captioned. Shown on quality.html.

Fails with E11030: confusingly similar variable names - rename for clarity

#!ek9
defines module bad.site.quality.similar

  defines function

    describeOrder()
      <- rtn as String?
      userId <- "customer-17"
      usersId <- "order-42"     //Similar to 'userId' - both String
      rtn: `${userId} ${usersId}` //A bug waiting to happen: which one did you mean?

    describeArticle()
      <- rtn as String?
      title <- "Quality"
      titles <- "Testing"       //Both String - the compiler CAN'T catch it if you swap them
      rtn: `${title} ${titles}`

Download quality_similar_bad.ek9 - it fails to compile on purpose, with the error its @Error line states.