The issue isn't contravariance but that higher ranked lifetimes can't have subtyping relations between them in rustc's implementation, so the fn pointer type is

The issue isn't contravariance but that higher ranked lifetimes can't have subtyping relations between them in rustc's implementation, so the fn pointer type is treated as a more general type than it is. This user is still wrong, the problem with rustc just isn't how it handles contravariance.