diff --git a/v1/ast/builtins.go b/v1/ast/builtins.go
index ece3575c71..2c3cd87ac9 100644
--- a/v1/ast/builtins.go
+++ b/v1/ast/builtins.go
@@ -3678,12 +3678,8 @@ func (b *Builtin) IsNondeterministic() bool {
 func (b *Builtin) Expr(operands ...*Term) *Expr {
 	ts := make([]*Term, len(operands)+1)
 	ts[0] = NewTerm(b.Ref())
-	for i := range operands {
-		ts[i+1] = operands[i]
-	}
-	return &Expr{
-		Terms: ts,
-	}
+	copy(ts[1:], operands)
+	return &Expr{Terms: ts}
 }
 
 // Call creates a new term for the built-in with the given operands.
diff --git a/v1/ast/check.go b/v1/ast/check.go
index ed3d14a15f..9460e1b6b9 100644
--- a/v1/ast/check.go
+++ b/v1/ast/check.go
@@ -655,12 +655,12 @@ func unify1(env *TypeEnv, term *Term, tpe types.Type, union bool) bool {
 		return unifies(env.GetByValue(v), tpe)
 	case Var:
 		if !union {
-			if exist := env.GetByValue(v); exist != nil {
+			if exist := env.GetByValue(term.Value); exist != nil {
 				return unifies(exist, tpe)
 			}
 			env.tree.PutOne(term.Value, tpe)
 		} else {
-			env.tree.PutOne(term.Value, types.Or(env.GetByValue(v), tpe))
+			env.tree.PutOne(term.Value, types.Or(env.GetByValue(term.Value), tpe))
 		}
 		return true
 	default:
@@ -955,9 +955,10 @@ func unifies(a, b types.Type) bool {
 		// NOTE(sr): variadic functions can only be internal ones, and we've forbidden
 		// their replacement via `with`; so we disregard variadic here
 		if types.Arity(a) == types.Arity(b) {
-			b := b.(*types.Function)
-			for i := range a.FuncArgs().Args {
-				if !unifies(a.FuncArgs().Arg(i), b.FuncArgs().Arg(i)) {
+			aArgs := a.FuncArgs()
+			bArgs := b.(*types.Function).FuncArgs()
+			for i := range aArgs.Args {
+				if !unifies(aArgs.Arg(i), bArgs.Arg(i)) {
 					return false
 				}
 			}
@@ -1195,9 +1196,7 @@ func getOneOfForNode(node *typeTreeNode) (result []Value) {
 		result = append(result, k)
 		return false
 	})
-
-	slices.SortFunc(result, Value.Compare)
-	return result
+	return util.SortedFunc(result, Value.Compare)
 }
 
 func getOneOfForType(tpe types.Type) (result []Value) {
@@ -1221,9 +1220,7 @@ func getOneOfForType(tpe types.Type) (result []Value) {
 		}
 	}
 
-	result = removeDuplicate(result)
-	slices.SortFunc(result, Value.Compare)
-	return result
+	return util.SortedFunc(removeDuplicate(result), Value.Compare)
 }
 
 func removeDuplicate(list []Value) []Value {
@@ -1273,16 +1270,11 @@ func override(ref Ref, t types.Type, o types.Type, rule *Rule) (types.Type, *Err
 	}
 	obj, ok := t.(*types.Object)
 	if !ok {
-		newType, err := getObjectType(ref, o, rule, dynamicAnyAny)
-		if err != nil {
-			return nil, err
-		}
-		return newType, nil
+		return getObjectType(ref, o, rule, dynamicAnyAny)
 	}
 	found := false
 	if ok {
-		staticProps := obj.StaticProperties()
-		for _, prop := range staticProps {
+		for _, prop := range obj.StaticProperties() {
 			valueCopy := prop.Value
 			key, err := InterfaceToValue(prop.Key)
 			if err != nil {
@@ -1329,8 +1321,7 @@ func getKeys(ref Ref, rule *Rule) ([]any, *Error) {
 
 func getObjectTypeRec(keys []any, o types.Type, d *types.DynamicProperty) *types.Object {
 	if len(keys) == 1 {
-		staticProps := []*types.StaticProperty{types.NewStaticProperty(keys[0], o)}
-		return types.NewObject(staticProps, d)
+		return types.NewObject([]*types.StaticProperty{types.NewStaticProperty(keys[0], o)}, d)
 	}
 
 	staticProps := []*types.StaticProperty{types.NewStaticProperty(keys[0], getObjectTypeRec(keys[1:], o, d))}
diff --git a/v1/types/types.go b/v1/types/types.go
index 030ca150f8..474265073c 100644
--- a/v1/types/types.go
+++ b/v1/types/types.go
@@ -964,9 +964,7 @@ func Compare(a, b Type) int {
 		}
 		return Compare(setA.of, setB.of)
 	case Any:
-		sl1 := typeSlice(a.(Any))
-		sl2 := typeSlice(b.(Any))
-		return typeSliceCompare(sl1, sl2)
+		return typeSliceCompare(typeSlice(a.(Any)), typeSlice(b.(Any)))
 	case *Function:
 		fA := a.(*Function)
 		fB := b.(*Function)