在这种情况下它执行赋值，然后返回b.

In this case it performs the assignment, then returns b.

这类东西可能会被编译器标记为一个无意的错误，通常你的意思是 a == b，所以你可能需要处理它.将其作为单独的一行进行，可以清楚地表明这是有意为之.

This sort of stuff might get flagged by the compiler as an inadvertent bug, usually you'd mean a == b, so you may need to deal with that. Doing it as a separate line makes it clear it's intentional.