Updated Proposal: Revisiting Implicits

[odersky]

@smarter

Here’s some examples of possible discussion topics I think might be worth going over:

• The Given Instances page has a section on instance initialization:

A given instance without type parameters or given clause is initialized on-demand, the first time it is accessed. It is not required to ensure safe publication, which means that different threads might create different instances for the same given definition. If a given definition has type parameters or a given clause, a fresh instance is created for each reference.

In fact that’s not true. We discussed this and agreed that given instances should ensure safe publication, and that’s what the implementation does (it uses a lazy val). The page on relationship with Scala-2 explicits is quite explicit that these things map to lazy vals and even includes the ForkJoin example that @soronpo inquires about. It seems the old wording was kept by an oversight in the cited quote.