语法 A city has been set up in what was once a wasteland.请分析下结

语法 A city has been set up in what was once a wasteland.请分析下结构
A city has been set up in what was a wasteland.请分析下结构
“in what was once a wasteland”做地点状语
“what was once a wasteland”做什么成分,请分析下