AW: switch exhaustiveness check not working within deconstruction pattern.

[redio.development at gmail.com]

I use VSCode with the "Extension Pack for Java".

I back checked on my (still linting) code using javac directly and it's in
fact not an error there. 

I assumed the (error) linting of the VSCode extension was based on javac
output.
But I guess it's a bug in their own code checking system unrelated to javac
output. 

I will open an issue on the extension instead.

Sorry to bother you and take your time for this.

 

Great regards 

RedIODev

 

Von: Jan Lahoda <jan.lahoda at oracle.com> 
Gesendet: Montag, 14. November 2022 12:41
An: redio.development at gmail.com; amber-dev at openjdk.org
Betreff: Re: switch exhaustiveness check not working within deconstruction
pattern. 

 

Hi,

 

This should indeed be exhaustive, AFAIK, and javac from JDK 19 seems to be
happy with the code:

---

$ ./javac --enable-preview -source 19 /tmp/Main.java 

Note: /tmp/Main.java uses preview features of Java SE 19.

Note: Recompile with -Xlint:preview for details. 

---

 

What are the precise steps to reproduce/JDK version?

 

Thanks,

    Jan

 

  _____  

From: amber-dev <amber-dev-retn at openjdk.org
<mailto:amber-dev-retn at openjdk.org> > on behalf of
redio.development at gmail.com <mailto:redio.development at gmail.com>
<redio.development at gmail.com <mailto:redio.development at gmail.com> >
Sent: Sunday, November 13, 2022 6:48 PM
To: amber-dev at openjdk.org <mailto:amber-dev at openjdk.org>
<amber-dev at openjdk.org <mailto:amber-dev at openjdk.org> >
Subject: switch exhaustiveness check not working within deconstruction
pattern. 

 

package dev.redio;

 

import static dev.redio.Main.Activity.*;

 

public class Main {

 

    public static void main(String[] args) {

        record Pair(boolean weekend, Activity activity) {}

        var pair = new Pair(true, new Sleeping(8));

        var msg = switch (pair) {   // <- A switch expression should have a
default case Java(1073743531)

            case Pair(boolean b, Sleeping s) -> "3";

            case Pair(boolean b, Skiing s) -> "4";

            case Pair(boolean b, Coding c) -> "5";

        };

        

        System.out.println(msg);

    }

 

    sealed interface Activity {

        record Sleeping(int hours) implements Activity {}

        record Skiing(String resort) implements Activity {}

        record Coding() implements Activity {}

    }

    

}

 

This deconstruction should be exhaustive since Pair is a guaranteed match
boolean doesn't have subclasses and Activity is sealed and fully covered. 

Null should throw in this case. A default case would never be reached. 

(Compiling and running with (dead) default case)

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