diff --git a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/AddSubTransformer.java b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/AddSubTransformer.java
deleted file mode 100644
index e65b5665..00000000
--- a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/AddSubTransformer.java
+++ /dev/null
@@ -1,53 +0,0 @@
-package dev.openrs2.deob.ast.transform;
-
-import com.github.javaparser.ast.CompilationUnit;
-import com.github.javaparser.ast.Node;
-import com.github.javaparser.ast.expr.BinaryExpr;
-import com.github.javaparser.ast.expr.Expression;
-import com.github.javaparser.ast.expr.UnaryExpr;
-import dev.openrs2.deob.ast.util.ExprUtils;
-import dev.openrs2.deob.ast.util.NodeUtils;
-import dev.openrs2.deob.ast.util.TypeUtils;
-
-public final class AddSubTransformer extends Transformer {
-	private static boolean isNegative(Expression expr) {
-		if (expr.isUnaryExpr()) {
-			return expr.asUnaryExpr().getOperator() == UnaryExpr.Operator.MINUS;
-		} else if (expr.isIntegerLiteralExpr()) {
-			return expr.asIntegerLiteralExpr().asInt() < 0;
-		} else if (expr.isLongLiteralExpr()) {
-			return expr.asLongLiteralExpr().asLong() < 0;
-		} else {
-			return false;
-		}
-	}
-
-	@Override
-	public void transform(CompilationUnit unit) {
-		NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, BinaryExpr.class, expr -> {
-			var op = expr.getOperator();
-			var left = expr.getLeft();
-			var right = expr.getRight();
-
-			var type = expr.calculateResolvedType();
-			if (op == BinaryExpr.Operator.PLUS && TypeUtils.isString(type)) {
-				return;
-			}
-
-			if (op == BinaryExpr.Operator.PLUS && isNegative(right)) {
-				/* x + -y => x - y */
-				expr.setOperator(BinaryExpr.Operator.MINUS);
-				expr.setRight(ExprUtils.negate(right));
-			} else if (op == BinaryExpr.Operator.PLUS && isNegative(left) && !(ExprUtils.hasSideEffects(left) && ExprUtils.hasSideEffects(right))) {
-				/* -x + y => y - x */
-				expr.setOperator(BinaryExpr.Operator.MINUS);
-				expr.setLeft(right.clone());
-				expr.setRight(ExprUtils.negate(left));
-			} else if (op == BinaryExpr.Operator.MINUS && isNegative(right)) {
-				/* x - -y => x + y */
-				expr.setOperator(BinaryExpr.Operator.PLUS);
-				expr.setRight(ExprUtils.negate(right));
-			}
-		});
-	}
-}
diff --git a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/AddSubTransformer.kt b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/AddSubTransformer.kt
new file mode 100644
index 00000000..75f1d6b9
--- /dev/null
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/AddSubTransformer.kt
@@ -0,0 +1,55 @@
+package dev.openrs2.deob.ast.transform
+
+import com.github.javaparser.ast.CompilationUnit
+import com.github.javaparser.ast.Node
+import com.github.javaparser.ast.expr.BinaryExpr
+import com.github.javaparser.ast.expr.Expression
+import com.github.javaparser.ast.expr.UnaryExpr
+import dev.openrs2.deob.ast.util.ExprUtils
+import dev.openrs2.deob.ast.util.NodeUtils
+import dev.openrs2.deob.ast.util.TypeUtils
+
+class AddSubTransformer : Transformer() {
+    override fun transform(unit: CompilationUnit) {
+        NodeUtils.walk(unit, Node.TreeTraversal.POSTORDER, BinaryExpr::class.java) { expr ->
+            val op = expr.operator
+            val left = expr.left
+            val right = expr.right
+            val type = expr.calculateResolvedType()
+
+            if (op == BinaryExpr.Operator.PLUS && TypeUtils.isString(type)) {
+                return@walk
+            }
+
+            if (op == BinaryExpr.Operator.PLUS && isNegative(right)) {
+                // x + -y => x - y
+                expr.operator = BinaryExpr.Operator.MINUS
+                expr.right = ExprUtils.negate(right)
+            } else if (op == BinaryExpr.Operator.PLUS && isNegative(left)) {
+                if (ExprUtils.hasSideEffects(left) || ExprUtils.hasSideEffects(right)) {
+                    return@walk
+                }
+
+                // -x + y => y - x
+                expr.operator = BinaryExpr.Operator.MINUS
+                expr.left = right.clone()
+                expr.right = ExprUtils.negate(left)
+            } else if (op == BinaryExpr.Operator.MINUS && isNegative(right)) {
+                // x - -y => x + y
+                expr.operator = BinaryExpr.Operator.PLUS
+                expr.right = ExprUtils.negate(right)
+            }
+        }
+    }
+
+    companion object {
+        private fun isNegative(expr: Expression): Boolean {
+            return when {
+                expr.isUnaryExpr -> expr.asUnaryExpr().operator == UnaryExpr.Operator.MINUS
+                expr.isIntegerLiteralExpr -> expr.asIntegerLiteralExpr().asInt() < 0
+                expr.isLongLiteralExpr -> expr.asLongLiteralExpr().asLong() < 0
+                else -> false
+            }
+        }
+    }
+}