Tracking down problems with function vs. constrained set type operators -\V/- & McWrath
Differentiating type operators and type sets (sort of) -\V/- & McWrath
Refactoring generic copy to be properly polymorphic -\V/- & McWrath
Moving 'occursIn' to types -\V/- & McWrath
Proper polymorphism of unify -\V/- & McWrath