Switch statement containing pattern case label element gets in the loop during execution

[Jan Lahoda]

Thanks for the report, Ilyas!


I've filled:

https://bugs.openjdk.java.net/browse/JDK-8269141


Thanks,

     Jan


On 22. 06. 21 10:37, Ilyas Selimov wrote:
> Hello!
>
> I tried to execute the code using OpenJDK 17 (build 17-ea+27-2476):
>
>     public static void main(String[] args) {
>         test(1);
>     }
>
>     static void test(Integer i) {
>         switch (i) {
>             case Integer o && o != null:
>                 System.out.println("s1");
>             default:
>                 System.out.println("def");
>         }
>     }
>
> and got the next output:
> s1
> def
> s1
> def
> ...
>
> As a result the switch statement gets in the loop.
> Looking at the bytecode of the method It seems the issue is related to 
> the latest goto instruction:
>
>  static void test(java.lang.Integer);
>     Code:
>        0: aload_0
>        1: dup
>        2: invokestatic  #19                 // Method 
> java/util/Objects.requireNonNull:
>        5: pop
>        6: astore_1
>        7: iconst_0
>        8: istore_2
>        9: aload_1
>       10: iload_2
>       11: invokedynamic #25,  0             // InvokeDynamic 
> #0:typeSwitch:(Ljava/lang/Object;I)I
>       16: lookupswitch  { // 1
>                      0: 36
>                default: 55
>           }
>       36: aload_1
>       37: astore_3
>       38: aload_3
>       39: ifnonnull     47
>       42: iconst_1
>       43: istore_2
>       44: goto          9
>       47: getstatic     #29                 // Field 
> java/lang/System.out:Ljava/io/PrintStream;
>       50: ldc           #35                 // String s1
>       52: invokevirtual #37                 // Method 
> java/io/PrintStream.println:(Ljava/lang/String;)V
>       55: getstatic     #29                 // Field 
> java/lang/System.out:Ljava/io/PrintStream;
>       58: ldc           #43                 // String def
>       60: invokevirtual #37                 // Method 
> java/io/PrintStream.println:(Ljava/lang/String;)V
>       63: goto          9
>
> Could somebody take a look?
>
> Thanks,
> Ilyas