Reviewing feedback on patterns in switch

Mark Raynsford mark at
Fri Jan 28 11:43:55 UTC 2022

On 2022-01-25T19:46:09 +0000
Brian Goetz <brian.goetz at> wrote:

> We’ve previewed patterns in switch for two rounds, and have received some feedback.  Overall, things work quite well, but there were a few items which received some nontrivial feedback, and I’m prepared to suggest some changes based on them.  I’ll summarize them here and create a new thread for each with a more detailed description.  
> I’ll make a call for additional items a little later; for now, let’s focus on these items before adding new things (or reopening old ones.)  
> 1.  Treatment of total patterns in switch / instanceof
> 2.  Positioning of guards
> 3.  Type refinements for GADTs
> 4.  Diamond for type patterns (and record patterns)


I'm a little late to the party, as ever, but is there a specific build I
should be looking at so that I can get a better idea of what the current
state of things are?

Mark Raynsford |

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