| WETyApp : WeakExpr -> WeakType -> WeakExpr
| WECoApp : WeakExpr -> WeakCoercion -> WeakExpr
| WELam : WeakExprVar -> WeakExpr -> WeakExpr
+(*
+| WEKappa : WeakExprVar -> WeakExpr -> WeakExpr
+| WEKappaApp : WeakExpr -> WeakExpr -> WeakExpr
+*)
| WETyLam : WeakTypeVar -> WeakExpr -> WeakExpr
| WECoLam : WeakCoerVar -> WeakExpr -> WeakExpr