为什么编译器声称这个类方法没有返回值？

The error I get from Eclipse is "No return, in function returning non-void." I added the default: case to see if it'd take away the error, but no beans. I thought it'd be okay to return an rvalue because it'd be copied-by-value onto the stack and thus a copy of the string would exist when the local variables of getLogLevelName() go out of scope. Indeed, the calling code works, but the error is mysterious to me.The error I get from Eclipse is "No return, in