diff --git a/src/ast/parser.rs b/src/ast/parser.rs
index 33627f8..29c3582 100644
--- a/src/ast/parser.rs
+++ b/src/ast/parser.rs
@@ -7,17 +7,14 @@ pub struct Parser {
 impl Parser {
     pub fn new(program: String) -> Parser {
         let program = program
-            .replace(' ', "")
-            .replace('\t', "")
-            .replace('\r', "")
-            .replace('\n', "");
+            .replace([' ', '\t', '\r', '\n'], "");
 
         Parser { program }
     }
 
     pub fn parse(&mut self) -> Vec<Instruction> {
         let (instructions, _) = self._parse(None, None);
-        return instructions;
+        instructions
     }
 
     fn _parse(&self, index: Option<usize>, stop_char: Option<char>) -> (Vec<Instruction>, usize) {
@@ -99,6 +96,6 @@ impl Parser {
             index += 1;
         }
 
-        return (instructions, index);
+        (instructions, index)
     }
 }
diff --git a/src/evaluation/cell.rs b/src/evaluation/cell.rs
index ba5780c..6015534 100644
--- a/src/evaluation/cell.rs
+++ b/src/evaluation/cell.rs
@@ -28,7 +28,7 @@ impl Cell {
     pub fn sub<T: PrimInt>(&mut self, value: T) {
         let sub: isize = self.value as isize - value.to_isize().unwrap();
         self.value = if sub < 0 {
-            u8::MAX - (sub.abs() as u8 - 1)
+            u8::MAX - (sub.unsigned_abs() as u8 - 1)
         } else {
             sub as u8
         };
diff --git a/src/evaluation/evaluator.rs b/src/evaluation/evaluator.rs
index d571b51..6a14b95 100644
--- a/src/evaluation/evaluator.rs
+++ b/src/evaluation/evaluator.rs
@@ -179,7 +179,7 @@ mod tests {
         let program = String::from("++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.");
         let mut parser = ast::Parser::new(program);
         let instructions = parser.parse();
-        let mut optimizer = optimization::Optimizer::new(instructions.clone());
+        let mut optimizer = optimization::Optimizer::new(instructions);
         let optimized_instructions = optimizer.optimize();
         let mut brainfuck = Evaluator::new(optimized_instructions);
         brainfuck.evaluate(None, Some(false));
@@ -195,7 +195,7 @@ mod tests {
         let program = String::from("{++++[>++++++++++++<-]>.}{++++[>++++++++++++<-]>+.}=");
         let mut parser = ast::Parser::new(program);
         let instructions = parser.parse();
-        let mut optimizer = optimization::Optimizer::new(instructions.clone());
+        let mut optimizer = optimization::Optimizer::new(instructions);
         let optimized_instructions = optimizer.optimize();
         let mut brainfuck = Evaluator::new(optimized_instructions);
         brainfuck.evaluate(None, Some(false));
@@ -207,7 +207,7 @@ mod tests {
         let program = String::from("{+++++[>+++++++++++++<-]>.<}==");
         let mut parser = ast::Parser::new(program);
         let instructions = parser.parse();
-        let mut optimizer = optimization::Optimizer::new(instructions.clone());
+        let mut optimizer = optimization::Optimizer::new(instructions);
         let optimized_instructions = optimizer.optimize();
         let mut brainfuck = Evaluator::new(optimized_instructions);
         brainfuck.evaluate(None, Some(false));
diff --git a/src/evaluation/scope.rs b/src/evaluation/scope.rs
index e1c5b21..fb813be 100644
--- a/src/evaluation/scope.rs
+++ b/src/evaluation/scope.rs
@@ -81,7 +81,7 @@ where
         let sub: isize = self.index as isize - amount as isize;
 
         self.index = if sub < 0 {
-            30000 - (sub.abs() as usize)
+            30000 - sub.unsigned_abs()
         } else {
             sub as usize
         }
diff --git a/src/main.rs b/src/main.rs
index ca5f6af..7cf3e6e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,7 +37,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     // Optimize the program if "optimize" is true
     if args.optimize {
-        let mut optimizer = optimization::Optimizer::new(instructions.clone());
+        let mut optimizer = optimization::Optimizer::new(instructions);
         let optimized_instructions = optimizer.optimize();
 
         // Evaluate the optimized program
diff --git a/src/optimization/optimizer.rs b/src/optimization/optimizer.rs
index f4fb5ec..5f0d15d 100644
--- a/src/optimization/optimizer.rs
+++ b/src/optimization/optimizer.rs
@@ -24,7 +24,7 @@ impl Optimizer {
         optimizer.optimize()
     }
 
-    fn merge_instructions(&self, optimized_instructions: &mut Vec<OptimizedInstruction>) -> () {
+    fn merge_instructions(&self, optimized_instructions: &mut Vec<OptimizedInstruction>) {
         for instruction in self.instructions.iter() {
             match optimized_instructions.last_mut() {
                 Some(last_optimized_instruction) => {
@@ -79,11 +79,11 @@ impl Optimizer {
     fn cancel_opposed_instructions(
         &self,
         optimized_instructions: &mut Vec<OptimizedInstruction>,
-    ) -> () {
+    ) {
         let mut new_optimized_instructions: Vec<OptimizedInstruction> = vec![];
 
         for optimized_instruction in optimized_instructions.iter() {
-            match new_optimized_instructions.last().clone() {
+            match new_optimized_instructions.last() {
                 Some(last_optimized_instruction) => {
                     if last_optimized_instruction.is_opposed(optimized_instruction) {
                         let last_amount = last_optimized_instruction.get_amount();
@@ -129,7 +129,7 @@ impl Optimizer {
         *optimized_instructions = new_optimized_instructions;
     }
 
-    fn recognize_patterns(&self, optimized_instructions: &mut Vec<OptimizedInstruction>) -> () {
+    fn recognize_patterns(&self, optimized_instructions: &mut Vec<OptimizedInstruction>) {
         let mut new_optimized_instructions: Vec<OptimizedInstruction> =
             optimized_instructions.clone();