diff --git a/dust-lang/src/compiler.rs b/dust-lang/src/compiler.rs
index 662fe2e..ddc52f4 100644
--- a/dust-lang/src/compiler.rs
+++ b/dust-lang/src/compiler.rs
@@ -778,6 +778,8 @@ impl<'src> Compiler<'src> {
             });
         }
 
+        if let Some([Operation::Test, Operation::Jump]) = self.get_last_operations() {}
+
         let (argument, push_back) = self.handle_binary_argument(&left_instruction)?;
 
         if push_back {
diff --git a/dust-lang/src/instruction/mod.rs b/dust-lang/src/instruction/mod.rs
index e7c03f6..fa8a82a 100644
--- a/dust-lang/src/instruction/mod.rs
+++ b/dust-lang/src/instruction/mod.rs
@@ -686,10 +686,10 @@ impl Instruction {
                     function,
                     argument_count,
                 } = Call::from(self);
-                let first_argument = destination.index().saturating_sub(argument_count);
-                let last_argument = destination.index() - 1;
+                let arguments_start = destination.index().saturating_sub(argument_count);
+                let arguments_end = arguments_start + argument_count;
 
-                format!("{destination} = {function}(R{first_argument}..=R{last_argument})")
+                format!("{destination} = {function}(R{arguments_start}..R{arguments_end})")
             }
             Operation::CallNative => {
                 let CallNative {
@@ -697,10 +697,10 @@ impl Instruction {
                     function,
                     argument_count,
                 } = CallNative::from(self);
-                let first_argument = destination.index().saturating_sub(argument_count);
-                let last_argument = destination.index() - 1;
+                let arguments_start = destination.index().saturating_sub(argument_count);
+                let arguments_end = arguments_start + argument_count;
 
-                format!("{destination} = {function}(R{first_argument}..=R{last_argument})")
+                format!("{destination} = {function}(R{arguments_start}..R{arguments_end})")
             }
             Operation::Return => {
                 let Return {
diff --git a/dust-lang/src/native_function/logic.rs b/dust-lang/src/native_function/logic.rs
index b250fc1..1dae66d 100644
--- a/dust-lang/src/native_function/logic.rs
+++ b/dust-lang/src/native_function/logic.rs
@@ -104,10 +104,6 @@ pub fn write<'a>(vm: &'a Vm<'a>, instruction: Instruction) -> Result<Option<Valu
     let first_argument = to_register.saturating_sub(argument_count);
 
     for argument_index in first_argument..to_register {
-        if argument_index != first_argument {
-            stdout.write(b" ").map_err(map_err)?;
-        }
-
         let argument = if let Some(value) = vm.open_register_allow_empty(argument_index)? {
             value
         } else {
@@ -137,10 +133,6 @@ pub fn write_line<'a>(vm: &'a Vm<'a>, instruction: Instruction) -> Result<Option
     let first_argument = to_register.saturating_sub(argument_count);
 
     for argument_index in first_argument..to_register {
-        if argument_index != first_argument {
-            stdout.write(b" ").map_err(map_err)?;
-        }
-
         let argument = if let Some(value) = vm.open_register_allow_empty(argument_index)? {
             value
         } else {