Add comment documenting why we can't use a simpler solution
Add comment documenting why we can't use a simpler solution

See #90144 for context.

r? @joshtriplett
aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust