Interesting switch pattern-matching snippets that don't compile but maybe should

[David Alayachew]

Am I missing something? Your first example does not compile.

I pulled down the early access 32 build, and the first example that you
said compiles fine, doesn't.

Here is the link I downloaded from --
https://download.java.net/java/early_access/jdk20/32/GPL/openjdk-20-ea+32_windows-x64_bin.zip

Here is my java --version output.

    openjdk 20-ea 2023-03-21
    OpenJDK Runtime Environment (build 20-ea+32-2328)
    OpenJDK 64-Bit Server VM (build 20-ea+32-2328, mixed mode, sharing)

And here is my javac --version output.

    javac 20-ea

And then here is what happens when I try to compile your first example.

---------

PotentialJavaBugs\src\main\java\io\github\davidalayachew\ShouldThisCompile.java:7:
error: invalid permits clause
sealed interface Base<T> extends Uber<T> permits Foo, Bar, Other{}
                                                           ^
  (subclass Other<T> must extend sealed class)
  where T is a type-variable:
    T extends Object declared in record Other
PotentialJavaBugs\src\main\java\io\github\davidalayachew\ShouldThisCompile.java:10:
error: class is not allowed to extend sealed class: Uber (as it is not
listed in its permits clause)
record Other<T>() implements Uber<T>{}
^
PotentialJavaBugs\src\main\java\io\github\davidalayachew\ShouldThisCompile.java:25:
error: incompatible types: Base<Integer> cannot be converted to
Other<Integer>
            case Other<Integer> o -> "Hello";
                 ^
PotentialJavaBugs\src\main\java\io\github\davidalayachew\ShouldThisCompile.java:39:
error: incompatible types: Base<Integer> cannot be converted to
Other<Integer>
            case Other<Integer> o -> "Hello";
                 ^
PotentialJavaBugs\src\main\java\io\github\davidalayachew\ShouldThisCompile.java:45:
error: incompatible types: Base<Integer> cannot be converted to
Other<Integer>
            case Other<Integer> o -> {
                 ^
Note:
PotentialJavaBugs\src\main\java\io\github\davidalayachew\ShouldThisCompile.java
uses preview features of Java SE 20.
Note: Recompile with -Xlint:preview for details.
5 errors

-----------

Please let me know if I am missing something.
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