chore: lint the project

The vm lint is unimportant but the other one is a bit more important
It could have actually caused a bug if I had not noticed it. An inaccurate
error message would have been printed.

src/interpreter/evaluator.rs

@@ -126,7 +126,9 @@ impl Evaluator {
             }
             Expression::FunctionCall(x) => {
                 let function = self.eval_expression(*x.function);
-                if Self::is_error(&function) {}
+                if Self::is_error(&function) {
+                    return function;
+                }
                 let args = self.eval_expressions(x.arguments);
                 if args.len() == 1 && Self::is_error(&args[0]) {
                     return args[0].clone();

src/vm/mod.rs

@@ -497,7 +497,7 @@ impl VM {
             Object::COMPILEDFUNCTION(func) => {
                 let mut closure = Closure::new(func);
 
-                for obj in self.stack[self.sp - num_free..self.sp].iter() {
+                for obj in &self.stack[self.sp - num_free..self.sp] {
                     closure.add_free_variable(obj.as_ref().clone());
                 }