Xcode stuck at “Attaching to (app name)”

My project failed to launch after I added a folder reference with the same name as one of the Group of the project.
Xcode didn't prompt me for any errors, but after sometime when I run my app on the simulator the console showed "error: failed to attach to process id 0" to me.

This drove me crazy.
Becoz remove the folder reference doesn't work, and even I opened a new blank project with the same Product Name doesn't work.
I turned to restart my computer and Xcode, used a new Product Name for my new project, and added that folder reference with a different name.

This used almost 3 hours to fix that.......

reference: StackOverflow