I find a new compiling bug in Flash 8:

function largerThanTen(n:Number):Boolean {
return n>0;
}
trace(largerThanTen(10));

Obviously, we won't, on purpose, change the > symbol(2nd line) into a plus operator. But, what if we want create a function that is used to do sth else but comparing numbers.
I accidentally changed the alter the "Boolean" to "String" and run it. Yes of course the compiler will tell us about a type mismatch out there. However, after I use plus operator, no warning for this kind:

function largerThanTen(n:Number):String {
return n+0;
}
trace(largerThanTen(10));

And what's more interesting is that I've also tried other operators, such as -, *, /, ^, etc., all of which will bring about an error reporting.
Could someone give us a reasonable explanation to this phenomenon?
I would rather classfy it as a compiling bug in Flash 8.

这是一个Flash 8的编译BUG吧我觉得。
<script>
function largerThanTen(n:Number):Boolean {
return n>0;
}
trace(largerThanTen(10));
</script>
明显，我们不会故意将 > 符号（第2行）错弄成 + 。但是，如果我们其实是想建一个不是用来比较的函数，又怎么办哩？
我当初是偶然把Boolean改为String，然后运行。当然，编译器会告訴我们说有“类型不匹配“，然而当我将 > 改为 + 后，就没有警告了：
<script>
function largerThanTen(n:Number):String {
return n+0;
}
trace(largerThanTen(10));
</script>更有趣的是，若我改为其它运算，如-,*,/,^等等，它们都会出现警告。
请问，有人能给出一个合理的解释么？