var _ vs _

[Cay Horstmann]

With JDK build 24, the following works:

    record Point(int x, int y) {}
    ...
    Point p = ...;
    String description = switch (p) {
       case Point(var x, var _) when x == 0 -> "on y-axis";
       case Point(_, var y) when y == 0 -> "on x-axis";
       case Point(var _, var _) -> "something else";
    };

But this switch is not deemed exhaustive:

    String description = switch (p) {
       case Point(var x, var _) when x == 0 -> "on y-axis";
       case Point(_, var y) when y == 0 -> "on x-axis";
       case Point(_, _) -> "something else";
    };

Is that a bug, or is there some subtle difference between var _ and _?

Thanks,

Cay

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Cay S. Horstmann | http://horstmann.com | mailto:cay at horstmann.com