02 Contravariance is the Dual of Covariance Implies Iterable is the Dual of Observable (Making Money Using Math) by Erik Meijer from error messages examples Watch Video

⏲ Duration: 36 min 19 sec
✓ Published: 23-Jun-2014

Description:
Every developer that has ever dealt with contra- and covariance in a modern OO language with generics, shivers with fear when they have to deal with these concepts in their code (except of course in Dart language, where all generic types are covariant).nTypically the solution is to click, click, click, click on the “suggested fix” by the IDE until the error messages finally go away. To add insult to injury, all this panic is for nothing since typically at runtime all generics are erased anyw