Auto merge of #44747 - Zoxc:gen-switch-unreachable, r=eddyb
Auto merge of #44747 - Zoxc:gen-switch-unreachable, r=eddyb

Make the fallback of generator resumption be unreachable instead of using return

GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust