The definition of
setUnfoldingInfoLazily is exactly the same as
setUnfoldingInfo and is only used in one place,
They were made equivalent in 2010 in 2ff2497d with the commit message.
commit 2ff2497dc374175b8ed81446258baf208d1f3e6e Author: Ian Lynagh <email@example.com> Wed Oct 20 15:37:10 2010 Committer: Ian Lynagh <firstname.lastname@example.org> Wed Oct 20 15:37:10 2010 Original File: compiler/basicTypes/IdInfo.lhs Don't seq unfoldings We generate intermediate unfoldings which are just thrown away, so evaluating them is a waste of time.