diff --git a/jasm-core/src/main/java/me/darknet/assembler/ast/specific/ASTMethod.java b/jasm-core/src/main/java/me/darknet/assembler/ast/specific/ASTMethod.java
index 3c3e019..119a618 100644
--- a/jasm-core/src/main/java/me/darknet/assembler/ast/specific/ASTMethod.java
+++ b/jasm-core/src/main/java/me/darknet/assembler/ast/specific/ASTMethod.java
@@ -54,10 +54,12 @@ public List<Instruction<?>> instructions() {
         return instructions;
     }
 
+    @SuppressWarnings("UnnecessaryLocalVariable")
     public void accept(ErrorCollector collector, ASTMethodVisitor visitor) {
         super.accept(collector, visitor);
-        for (int i = 0; i < parameters.size(); i++) {
-            visitor.visitParameter(i, parameters.get(i));
+        List<ASTIdentifier> localParams = parameters;
+        for (int i = 0; i < localParams.size(); i++) {
+            visitor.visitParameter(i, localParams.get(i));
         }
         if(this.code == null) {
             visitor.visitEnd();
@@ -69,13 +71,14 @@ public void accept(ErrorCollector collector, ASTMethodVisitor visitor) {
         };
         if (instructionVisitor != null) {
             int instructionIndex = 0;
-            for (int i = 0; i < code.instructions().size(); i++) {
-                ASTInstruction instruction = code.instructions().get(i);
-                if(instruction instanceof ASTLabel lab) {
+            List<ASTInstruction> localAstInstructions = code.instructions();
+            List<Instruction<?>> localIrInstructions = instructions;
+            for (ASTInstruction instruction : localAstInstructions) {
+                if (instruction instanceof ASTLabel lab) {
                     instructionVisitor.visitLabel(lab.identifier());
                 } else {
                     instructionVisitor.visitInstruction(instruction);
-                    instructions.get(instructionIndex++).transform(instruction, instructionVisitor);
+                    localIrInstructions.get(instructionIndex++).transform(instruction, instructionVisitor);
                 }
             }
 
diff --git a/jasm-core/src/main/java/me/darknet/assembler/transformer/Transformer.java b/jasm-core/src/main/java/me/darknet/assembler/transformer/Transformer.java
index f97ecbc..7791186 100644
--- a/jasm-core/src/main/java/me/darknet/assembler/transformer/Transformer.java
+++ b/jasm-core/src/main/java/me/darknet/assembler/transformer/Transformer.java
@@ -29,13 +29,14 @@ public Transformer(ASTRootVisitor visitor) {
      */
     public Result<Void> transform(List<ASTElement> declarations) {
         ErrorCollector collector = new ErrorCollector();
+        ASTRootVisitor localVisitor = visitor;
         for (ASTElement declaration : declarations) {
             if (declaration instanceof ASTField field) {
-                field.accept(collector, visitor.visitField(field.modifiers(), field.name(), field.descriptor()));
+                field.accept(collector, localVisitor.visitField(field.modifiers(), field.name(), field.descriptor()));
             } else if (declaration instanceof ASTMethod method) {
-                method.accept(collector, visitor.visitMethod(method.modifiers(), method.name(), method.descriptor()));
+                method.accept(collector, localVisitor.visitMethod(method.modifiers(), method.name(), method.descriptor()));
             } else if (declaration instanceof ASTClass clazz) {
-                clazz.accept(collector, visitor.visitClass(clazz.modifiers(), clazz.name()));
+                clazz.accept(collector, localVisitor.visitClass(clazz.modifiers(), clazz.name()));
             } else {
                 collector.addError("Don't know how to process: " + declaration.type(), declaration.location());
             }