We have noticed that the compile_no_archive task introduced in SERVER-48893 can sometimes take a very long time to complete, as evidenced in this commit queue build:

https://evergreen.mongodb.com/version/5f7e4121a4cf472a94da030f

Most of the time seems to be spent compiling source files, some of which take upwards of 20 seconds to complete. This is locally reproducible as well. We need to find out if there is a commit which introduced a parsing problem somewhere and fix it.