The document states that SwitchBoostraps.typeSwitch() throws
IllegalArgumentException - if the invocation type is not a method type of first parameter of a reference type, second parameter of type int and with int as its return type

In the following case, when the first param is not a ref type, IAE is expected but not thrown.
        SwitchBootstraps.typeSwitch(
                LOOKUP,
                DUMMY_INVOCATION_NAME,
                MethodType.methodType(
                        int.class, int.class, int.class // <- First param is int.class and not a reference type.
                ),
                LABELS);

Also, the following exception is not thrown:
    IllegalArgumentException - if labels contains an element that is not of type Boolean when target is a Boolean.class

        var labels = new Object[]{5, 10};
        CallSite callSite = SwitchBootstraps.typeSwitch(
                LOOKUP,
                DUMMY_INVOCATION_NAME,
                MethodType.methodType(
                        int.class, Boolean.class, int.class
                ),
                labels
        );
        callSite.getTarget().invoke(true, 0);