Auto merge of #5286 - matthiaskrgr:delay_vec_creation, r=flip1995
Auto merge of #5286 - matthiaskrgr:delay_vec_creation, r=flip1995

check_pat: delay creation of the "normal" vec until we reach the branch where it is actually needed

changelog: none

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