Both LWG 3281 "Conversion from pair-like types to subrange is a silent semantic promotion" and LWG 3282 "subrange converting constructor should disallow derived to base conversions" removed subrange's hated implicit conversions from pair-like types. Notably, neither issue removed the two "iterator-sentinel-pair" deduction guides which target the removed constructors nor the exposition-only iterator-sentinel-pair concept itself, all of which are now useless.