Auto merge of #27182 - AlisdairO:diagnostics382, r=Manishearth
Auto merge of #27182 - AlisdairO:diagnostics382, r=Manishearth

As title :-)
Part of #24407.

r? @Manishearth

GBGamer/rust,graydon/rust,zubron/rust,dwillmer/rust,pshc/rust,aidancully/rust,GBGamer/rust,dwillmer/rust,dwillmer/rust,GBGamer/rust,zubron/rust,aidancully/rust,pshc/rust,zubron/rust,zubron/rust,pshc/rust,GBGamer/rust,dwillmer/rust,GBGamer/rust,dwillmer/rust,aidancully/rust,zubron/rust,pshc/rust,aidancully/rust,graydon/rust,zubron/rust,pshc/rust,graydon/rust,dwillmer/rust,dwillmer/rust,graydon/rust,zubron/rust,pshc/rust,zubron/rust,graydon/rust,GBGamer/rust,pshc/rust,GBGamer/rust,dwillmer/rust,pshc/rust,aidancully/rust,aidancully/rust,GBGamer/rust,graydon/rust