RFR: 8314578: Non-verifiable code is emitted when two guards declare pattern variables in colon-switch

[Remi Forax]

----- Original Message -----
> From: "Aggelos Biboudis" <abimpoudis at openjdk.org>
> To: "compiler-dev" <compiler-dev at openjdk.org>
> Sent: Monday, October 2, 2023 12:19:40 PM
> Subject: RFR: 8314578: Non-verifiable code is emitted when two guards declare pattern variables in colon-switch

> In the following example while the case pattern does not introduce binding
> variable, the guard does. `hasBindings` has been updated accordingly to accept
> any trees and check them if they contain a `visitBindingPattern`. Not only
> `JCPattern`'s.
> 
> 
> static void test(Object o) {
>    switch (o) {
>      case R1() when o instanceof String s:
>      case R2() when o instanceof Integer i:
>        System.out.println("hello: " + i);
>        break;
>      default:
>        break;
>    }
>  }

I think, i've fully understand the issue, what about

static void test(Object o) {
   switch (o) {
     case R1() when o instanceof String _:
     case R2() when o instanceof Integer _:
       System.out.println("hello: " + i);
       break;
     default:
       break;
   }
 }

regards,
Rémi

> 
> -------------
> 
> Commit messages:
> - 8314578: Non-verifiable code is emitted when two guards declare pattern
> variables in colon-switch
> 
> Changes: https://git.openjdk.org/jdk/pull/15630/files
> Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15630&range=00
>  Issue: https://bugs.openjdk.org/browse/JDK-8314578
>  Stats: 41 lines in 3 files changed: 38 ins; 0 del; 3 mod
>  Patch: https://git.openjdk.org/jdk/pull/15630.diff
>  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15630/head:pull/15630
> 
> PR: https://git.openjdk.org/jdk/pull/15630