$ javac broken/SealedViolation.java     (17.0.20.1)
broken/SealedViolation.java:5: error: class is not allowed to extend sealed class: Shape (as it is not listed in its permits clause)
    record Triangle(double b, double h) implements Shape {}
    ^
1 error

$ javac broken/RecordFieldMutation.java     (17.0.20.1)
broken/RecordFieldMutation.java:3: error: cannot assign a value to final variable x
    record Point(int x, int y) { void move() { this.x = 10; } }
                                                   ^
1 error

$ javac broken/SwitchPatternOn17.java     (17.0.20.1)
broken/SwitchPatternOn17.java:3: error: patterns in switch statements are a preview feature and are disabled by default.
    static String f(Object o) { return switch (o) { case String s -> "string"; default -> "other"; }; }
                                                         ^
  (use --enable-preview to enable patterns in switch statements)
1 error