Code:

class Test {
  public static void main(String[] args) {
    test(1);
    test("hello");
  }

  record R1() {}
  record R2() {}
  
  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;
    }
  }
}

Expected: should not be compilable: pattern variables declared in guard should not be visible in the switch label body.

Actual: Compilable (even without preview) and produces VerifyError at runtime:

Exception in thread "main" java.lang.VerifyError: Bad local variable type
Exception Details:
  Location:
    Test.test(Ljava/lang/Object;)V @73: aload_2
  Reason:
    Type integer (current frame, locals[2]) is not assignable to reference type
  Current Frame:
    bci: @73
    flags: { }
    locals: { 'java/lang/Object', 'java/lang/Object', integer }
    stack: { 'java/io/PrintStream' }
  Bytecode:
    0000000: 2a59 b800 1557 4c03 3d2b 1cba 001b 0000
    0000010: ab00 0000 0000 0045 0000 0002 0000 0000
    0000020: 0000 001c 0000 0001 0000 0036 2bc0 001f
    0000030: 4e2a c100 2199 000c 2ac0 0021 3a04 a700
    0000040: 0804 3da7 ffc6 b200 232c ba00 2900 00b6
    0000050: 002d a700 06a7 0003 b1
  Stackmap Table:
    append_frame(@9,Object[#2],Integer)
    same_frame(@44)
    append_frame(@65,Object[#31])
    chop_frame(@70,1)
    same_frame(@85)
    chop_frame(@88,2)

at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:537)
at java.base/java.lang.Class.forName(Class.java:516)
at jdk.compiler/com.sun.tools.javac.launcher.Main.execute(Main.java:432)
at jdk.compiler/com.sun.tools.javac.launcher.Main.run(Main.java:208)
at jdk.compiler/com.sun.tools.javac.launcher.Main.main(Main.java:135)