generics: problem with type inference for recursive methods

class Bug2
{
static <T> boolean isOK(T x)
{
return isOK(x);
}

static <T> boolean isStillOK(T x)
{
return true && isOK(x);
}

static <T> boolean isNoMoreOK(T x)
{
return true && isNoMoreOK(x);
// incompatible.types
// found: <T>boolean
// required: java.lang.Object
}

static <T> boolean isOKAgain(T x)
{
boolean res;
return true && (res = isOKAgain(x));
}
}