diff --git a/dust-lang/src/chunk.rs b/dust-lang/src/chunk.rs
index 2b643d1..13d5b3a 100644
--- a/dust-lang/src/chunk.rs
+++ b/dust-lang/src/chunk.rs
@@ -18,7 +18,7 @@ pub struct Chunk {
     name: Option<String>,
     r#type: FunctionType,
 
-    instructions: Vec<(Instruction, Type, Span)>,
+    instructions: Vec<(Instruction, Span)>,
     constants: Vec<ConcreteValue>,
     locals: Vec<Local>,
 }
@@ -41,7 +41,7 @@ impl Chunk {
     pub fn with_data(
         name: Option<String>,
         r#type: FunctionType,
-        instructions: Vec<(Instruction, Type, Span)>,
+        instructions: Vec<(Instruction, Span)>,
         constants: Vec<ConcreteValue>,
         locals: Vec<Local>,
     ) -> Self {
@@ -74,7 +74,7 @@ impl Chunk {
         &self.constants
     }
 
-    pub fn instructions(&self) -> &Vec<(Instruction, Type, Span)> {
+    pub fn instructions(&self) -> &Vec<(Instruction, Span)> {
         &self.instructions
     }
 
diff --git a/dust-lang/src/compiler.rs b/dust-lang/src/compiler.rs
index 58f16eb..22e60a8 100644
--- a/dust-lang/src/compiler.rs
+++ b/dust-lang/src/compiler.rs
@@ -112,11 +112,16 @@ impl<'src> Compiler<'src> {
             value_parameters,
             return_type: Box::new(self.return_type.unwrap_or(Type::None)),
         };
+        let instructions = self
+            .instructions
+            .into_iter()
+            .map(|(i, _, s)| (i, s))
+            .collect();
 
         Chunk::with_data(
             self.self_name,
             r#type,
-            self.instructions,
+            instructions,
             self.constants,
             self.locals,
         )
diff --git a/dust-lang/src/disassembler.rs b/dust-lang/src/disassembler.rs
index 664bf86..02105a3 100644
--- a/dust-lang/src/disassembler.rs
+++ b/dust-lang/src/disassembler.rs
@@ -47,8 +47,8 @@ use crate::{value::ConcreteValue, Chunk, Local};
 const INSTRUCTION_HEADER: [&str; 4] = [
     "Instructions",
     "------------",
-    " i   POSITION    OPERATION        TYPE                    INFO              ",
-    "--- ---------- ------------- -------------- --------------------------------",
+    " i   POSITION    OPERATION                 INFO              ",
+    "--- ---------- ------------- --------------------------------",
 ];
 
 const CONSTANT_HEADER: [&str; 4] = [
@@ -61,8 +61,8 @@ const CONSTANT_HEADER: [&str; 4] = [
 const LOCAL_HEADER: [&str; 4] = [
     "Locals",
     "------",
-    " i   SCOPE  MUTABLE               TYPE                  IDENTIFIER   ",
-    "--- ------- ------- -------------------------------- ----------------",
+    " i   SCOPE  MUTABLE       TYPE          IDENTIFIER   ",
+    "--- ------- ------- ---------------- ----------------",
 ];
 
 /// Builder that constructs a human-readable representation of a chunk.
@@ -89,11 +89,11 @@ impl<'a> Disassembler<'a> {
         }
     }
 
-    /// The default width of the disassembly output, including borders.
+    /// The default width of the disassembly output, including borders and padding.
     pub fn default_width() -> usize {
         let longest_line = INSTRUCTION_HEADER[3];
 
-        (longest_line.chars().count() + 2).max(80)
+        longest_line.chars().count() + 4 // Allow for one border and one padding space on each side.
     }
 
     pub fn source(mut self, source: &'a str) -> Self {
@@ -209,22 +209,12 @@ impl<'a> Disassembler<'a> {
             self.push_header(line);
         }
 
-        for (index, (instruction, r#type, position)) in self.chunk.instructions().iter().enumerate()
-        {
+        for (index, (instruction, position)) in self.chunk.instructions().iter().enumerate() {
             let position = position.to_string();
             let operation = instruction.operation().to_string();
-            let type_display = {
-                let mut type_string = r#type.to_string();
-
-                if type_string.len() > 14 {
-                    type_string = format!("{type_string:.11}...");
-                }
-
-                type_string
-            };
             let info = instruction.disassembly_info();
             let instruction_display =
-                format!("{index:^3} {position:^10} {operation:13} {type_display:^14} {info:^32}");
+                format!("{index:^3} {position:^10} {operation:13} {info:^32}");
 
             self.push_details(&instruction_display);
         }
@@ -254,7 +244,7 @@ impl<'a> Disassembler<'a> {
             let type_display = r#type.to_string();
             let scope = scope.to_string();
             let local_display = format!(
-                "{index:^3} {scope:^7} {is_mutable:^7} {type_display:^32} {identifier_display:^16}"
+                "{index:^3} {scope:^7} {is_mutable:^7} {type_display:^16} {identifier_display:^16}"
             );
 
             self.push_details(&local_display);
diff --git a/dust-lang/src/vm.rs b/dust-lang/src/vm.rs
index 934f1b6..e713479 100644
--- a/dust-lang/src/vm.rs
+++ b/dust-lang/src/vm.rs
@@ -715,13 +715,12 @@ impl<'a> Vm<'a> {
     }
 
     fn read(&mut self) -> Result<Instruction, VmError> {
-        let (instruction, _type, position) =
-            self.chunk.instructions().get(self.ip).ok_or_else(|| {
-                VmError::InstructionIndexOutOfBounds {
-                    index: self.ip,
-                    position: self.current_position,
-                }
-            })?;
+        let (instruction, position) = self.chunk.instructions().get(self.ip).ok_or_else(|| {
+            VmError::InstructionIndexOutOfBounds {
+                index: self.ip,
+                position: self.current_position,
+            }
+        })?;
 
         self.ip += 1;
         self.current_position = *position;
diff --git a/dust-lang/tests/basic.rs b/dust-lang/tests/basic.rs
index f6be57e..c6378bb 100644
--- a/dust-lang/tests/basic.rs
+++ b/dust-lang/tests/basic.rs
@@ -16,10 +16,9 @@ fn constant() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(0, 2)
                 ),
-                (Instruction::r#return(true), Type::None, Span(2, 2))
+                (Instruction::r#return(true), Span(2, 2))
             ],
             vec![ConcreteValue::Integer(42)],
             vec![]
@@ -42,7 +41,7 @@ fn empty() {
                 value_parameters: None,
                 return_type: Box::new(Type::None)
             },
-            vec![(Instruction::r#return(false), Type::None, Span(0, 0))],
+            vec![(Instruction::r#return(false), Span(0, 0))],
             vec![],
             vec![]
         ))
@@ -70,7 +69,6 @@ fn parentheses_precedence() {
                         Argument::Constant(0),
                         Argument::Constant(1)
                     ),
-                    Type::Integer,
                     Span(3, 4)
                 ),
                 (
@@ -79,10 +77,9 @@ fn parentheses_precedence() {
                         Argument::Register(0),
                         Argument::Constant(2)
                     ),
-                    Type::Integer,
                     Span(8, 9)
                 ),
-                (Instruction::r#return(true), Type::None, Span(11, 11)),
+                (Instruction::r#return(true), Span(11, 11)),
             ],
             vec![
                 ConcreteValue::Integer(1),
diff --git a/dust-lang/tests/comparison.rs b/dust-lang/tests/comparison.rs
index 1b19be9..095a184 100644
--- a/dust-lang/tests/comparison.rs
+++ b/dust-lang/tests/comparison.rs
@@ -16,21 +16,18 @@ fn equal() {
             vec![
                 (
                     Instruction::equal(true, Argument::Constant(0), Argument::Constant(1)),
-                    Type::None,
                     Span(2, 4)
                 ),
-                (Instruction::jump(1, true), Type::None, Span(2, 4)),
+                (Instruction::jump(1, true), Span(2, 4)),
                 (
                     Instruction::load_boolean(Destination::Register(0), true, true),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
                 (
                     Instruction::load_boolean(Destination::Register(0), false, false),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
-                (Instruction::r#return(true), Type::None, Span(6, 6)),
+                (Instruction::r#return(true), Span(6, 6)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -56,21 +53,18 @@ fn greater() {
             vec![
                 (
                     Instruction::less_equal(false, Argument::Constant(0), Argument::Constant(1)),
-                    Type::None,
                     Span(2, 3)
                 ),
-                (Instruction::jump(1, true), Type::None, Span(2, 3)),
+                (Instruction::jump(1, true), Span(2, 3)),
                 (
                     Instruction::load_boolean(Destination::Register(0), true, true),
-                    Type::Boolean,
                     Span(2, 3)
                 ),
                 (
                     Instruction::load_boolean(Destination::Register(0), false, false),
-                    Type::Boolean,
                     Span(2, 3)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5)),
+                (Instruction::r#return(true), Span(5, 5)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -96,21 +90,18 @@ fn greater_than_or_equal() {
             vec![
                 (
                     Instruction::less(false, Argument::Constant(0), Argument::Constant(1)),
-                    Type::None,
                     Span(2, 4)
                 ),
-                (Instruction::jump(1, true), Type::None, Span(2, 4)),
+                (Instruction::jump(1, true), Span(2, 4)),
                 (
                     Instruction::load_boolean(Destination::Register(0), true, true),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
                 (
                     Instruction::load_boolean(Destination::Register(0), false, false),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
-                (Instruction::r#return(true), Type::None, Span(6, 6)),
+                (Instruction::r#return(true), Span(6, 6)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -136,21 +127,18 @@ fn less_than() {
             vec![
                 (
                     Instruction::less(true, Argument::Constant(0), Argument::Constant(1)),
-                    Type::None,
                     Span(2, 3)
                 ),
-                (Instruction::jump(1, true), Type::None, Span(2, 3)),
+                (Instruction::jump(1, true), Span(2, 3)),
                 (
                     Instruction::load_boolean(Destination::Register(0), true, true),
-                    Type::Boolean,
                     Span(2, 3)
                 ),
                 (
                     Instruction::load_boolean(Destination::Register(0), false, false),
-                    Type::Boolean,
                     Span(2, 3)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5)),
+                (Instruction::r#return(true), Span(5, 5)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -176,21 +164,18 @@ fn less_than_or_equal() {
             vec![
                 (
                     Instruction::less_equal(true, Argument::Constant(0), Argument::Constant(1)),
-                    Type::None,
                     Span(2, 4)
                 ),
-                (Instruction::jump(1, true), Type::None, Span(2, 4)),
+                (Instruction::jump(1, true), Span(2, 4)),
                 (
                     Instruction::load_boolean(Destination::Register(0), true, true),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
                 (
                     Instruction::load_boolean(Destination::Register(0), false, false),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
-                (Instruction::r#return(true), Type::None, Span(6, 6)),
+                (Instruction::r#return(true), Span(6, 6)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -216,21 +201,18 @@ fn not_equal() {
             vec![
                 (
                     Instruction::equal(false, Argument::Constant(0), Argument::Constant(1)),
-                    Type::None,
                     Span(2, 4)
                 ),
-                (Instruction::jump(1, true), Type::None, Span(2, 4)),
+                (Instruction::jump(1, true), Span(2, 4)),
                 (
                     Instruction::load_boolean(Destination::Register(0), true, true),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
                 (
                     Instruction::load_boolean(Destination::Register(0), false, false),
-                    Type::Boolean,
                     Span(2, 4)
                 ),
-                (Instruction::r#return(true), Type::None, Span(6, 6)),
+                (Instruction::r#return(true), Span(6, 6)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
diff --git a/dust-lang/tests/functions.rs b/dust-lang/tests/functions.rs
index 6eab230..de353d2 100644
--- a/dust-lang/tests/functions.rs
+++ b/dust-lang/tests/functions.rs
@@ -24,10 +24,9 @@ fn function() {
                         Argument::Local(0),
                         Argument::Local(1)
                     ),
-                    Type::Integer,
                     Span(30, 31)
                 ),
-                (Instruction::r#return(true), Type::None, Span(35, 35)),
+                (Instruction::r#return(true), Span(35, 35)),
             ],
             vec![ConcreteValue::string("a"), ConcreteValue::string("b"),],
             vec![
@@ -54,29 +53,21 @@ fn function_call() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Function(FunctionType {
-                        type_parameters: None,
-                        value_parameters: Some(vec![(0, Type::Integer), (1, Type::Integer)]),
-                        return_type: Box::new(Type::Integer),
-                    }),
                     Span(0, 36)
                 ),
                 (
                     Instruction::load_constant(Destination::Register(1), 1, false),
-                    Type::Integer,
                     Span(36, 37)
                 ),
                 (
                     Instruction::load_constant(Destination::Register(2), 2, false),
-                    Type::Integer,
                     Span(39, 40)
                 ),
                 (
                     Instruction::call(Destination::Register(3), Argument::Constant(0), 2),
-                    Type::Integer,
                     Span(35, 41)
                 ),
-                (Instruction::r#return(true), Type::None, Span(41, 41)),
+                (Instruction::r#return(true), Span(41, 41)),
             ],
             vec![
                 ConcreteValue::Function(Chunk::with_data(
@@ -93,10 +84,9 @@ fn function_call() {
                                 Argument::Local(0),
                                 Argument::Local(1)
                             ),
-                            Type::Integer,
                             Span(30, 31)
                         ),
-                        (Instruction::r#return(true), Type::None, Span(35, 36)),
+                        (Instruction::r#return(true), Span(35, 36)),
                     ],
                     vec![ConcreteValue::string("a"), ConcreteValue::string("b"),],
                     vec![
@@ -130,19 +120,10 @@ fn function_declaration() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Function(FunctionType {
-                        type_parameters: None,
-                        value_parameters: Some(vec![(0, Type::Integer), (1, Type::Integer)]),
-                        return_type: Box::new(Type::Integer),
-                    }),
                     Span(0, 40)
                 ),
-                (
-                    Instruction::define_local(0, 0, false),
-                    Type::None,
-                    Span(3, 6)
-                ),
-                (Instruction::r#return(false), Type::None, Span(40, 40))
+                (Instruction::define_local(0, 0, false), Span(3, 6)),
+                (Instruction::r#return(false), Span(40, 40))
             ],
             vec![
                 ConcreteValue::Function(Chunk::with_data(
@@ -159,10 +140,9 @@ fn function_declaration() {
                                 Argument::Local(0),
                                 Argument::Local(1)
                             ),
-                            Type::Integer,
                             Span(35, 36)
                         ),
-                        (Instruction::r#return(true), Type::None, Span(40, 40)),
+                        (Instruction::r#return(true), Span(40, 40)),
                     ],
                     vec![ConcreteValue::string("a"), ConcreteValue::string("b")],
                     vec![
diff --git a/dust-lang/tests/lists.rs b/dust-lang/tests/lists.rs
index c8fcd5e..aa6eaac 100644
--- a/dust-lang/tests/lists.rs
+++ b/dust-lang/tests/lists.rs
@@ -16,10 +16,9 @@ fn empty_list() {
             vec![
                 (
                     Instruction::load_list(Destination::Register(0), 0),
-                    Type::List(Box::new(Type::Any)),
                     Span(0, 2)
                 ),
-                (Instruction::r#return(true), Type::None, Span(2, 2)),
+                (Instruction::r#return(true), Span(2, 2)),
             ],
             vec![],
             vec![]
@@ -45,25 +44,21 @@ fn list() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(1, 2)
                 ),
                 (
                     Instruction::load_constant(Destination::Register(1), 1, false),
-                    Type::Integer,
                     Span(4, 5)
                 ),
                 (
                     Instruction::load_constant(Destination::Register(2), 2, false),
-                    Type::Integer,
                     Span(7, 8)
                 ),
                 (
                     Instruction::load_list(Destination::Register(3), 0),
-                    Type::List(Box::new(Type::Integer)),
                     Span(0, 9)
                 ),
-                (Instruction::r#return(true), Type::None, Span(9, 9)),
+                (Instruction::r#return(true), Span(9, 9)),
             ],
             vec![
                 ConcreteValue::Integer(1),
@@ -100,7 +95,6 @@ fn list_with_complex_expression() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(1, 2)
                 ),
                 (
@@ -109,7 +103,6 @@ fn list_with_complex_expression() {
                         Argument::Constant(1),
                         Argument::Constant(2)
                     ),
-                    Type::Integer,
                     Span(6, 7)
                 ),
                 (
@@ -118,7 +111,6 @@ fn list_with_complex_expression() {
                         Argument::Constant(3),
                         Argument::Constant(4)
                     ),
-                    Type::Integer,
                     Span(14, 15)
                 ),
                 (
@@ -127,16 +119,14 @@ fn list_with_complex_expression() {
                         Argument::Register(1),
                         Argument::Register(2)
                     ),
-                    Type::Integer,
                     Span(10, 11)
                 ),
-                (Instruction::close(1, 3), Type::None, Span(17, 18)),
+                (Instruction::close(1, 3), Span(17, 18)),
                 (
                     Instruction::load_list(Destination::Register(4), 0),
-                    Type::List(Box::new(Type::Integer)),
                     Span(0, 18)
                 ),
-                (Instruction::r#return(true), Type::None, Span(18, 18)),
+                (Instruction::r#return(true), Span(18, 18)),
             ],
             vec![
                 ConcreteValue::Integer(1),
@@ -174,7 +164,6 @@ fn list_with_simple_expression() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(1, 2)
                 ),
                 (
@@ -183,20 +172,17 @@ fn list_with_simple_expression() {
                         Argument::Constant(1),
                         Argument::Constant(2)
                     ),
-                    Type::Integer,
                     Span(6, 7)
                 ),
                 (
                     Instruction::load_constant(Destination::Register(2), 3, false),
-                    Type::Integer,
                     Span(11, 12)
                 ),
                 (
                     Instruction::load_list(Destination::Register(3), 0),
-                    Type::List(Box::new(Type::Integer)),
                     Span(0, 13)
                 ),
-                (Instruction::r#return(true), Type::None, Span(13, 13)),
+                (Instruction::r#return(true), Span(13, 13)),
             ],
             vec![
                 ConcreteValue::Integer(1),
diff --git a/dust-lang/tests/logic.rs b/dust-lang/tests/logic.rs
deleted file mode 100644
index 5b1784c..0000000
--- a/dust-lang/tests/logic.rs
+++ /dev/null
@@ -1,160 +0,0 @@
-use dust_lang::*;
-
-#[test]
-fn and() {
-    let source = "true && false";
-
-    assert_eq!(
-        compile(source),
-        Ok(Chunk::with_data(
-            None,
-            FunctionType {
-                type_parameters: None,
-                value_parameters: None,
-                return_type: Box::new(Type::Boolean),
-            },
-            vec![
-                (
-                    Instruction::load_boolean(Destination::Register(0), true, false),
-                    Type::Boolean,
-                    Span(0, 4)
-                ),
-                (
-                    Instruction::test(Argument::Register(0), true),
-                    Type::None,
-                    Span(5, 7)
-                ),
-                (Instruction::jump(1, true), Type::None, Span(5, 7)),
-                (
-                    Instruction::load_boolean(Destination::Register(1), false, false),
-                    Type::Boolean,
-                    Span(8, 13)
-                ),
-                (Instruction::r#return(true), Type::None, Span(13, 13)),
-            ],
-            vec![],
-            vec![]
-        ))
-    );
-
-    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(false))));
-}
-
-#[test]
-fn or() {
-    let source = "true || false";
-
-    assert_eq!(
-        compile(source),
-        Ok(Chunk::with_data(
-            None,
-            FunctionType {
-                type_parameters: None,
-                value_parameters: None,
-                return_type: Box::new(Type::Boolean),
-            },
-            vec![
-                (
-                    Instruction::load_boolean(Destination::Register(0), true, false),
-                    Type::Boolean,
-                    Span(0, 4)
-                ),
-                (
-                    Instruction::test(Argument::Register(0), false),
-                    Type::None,
-                    Span(5, 7)
-                ),
-                (Instruction::jump(1, true), Type::None, Span(5, 7)),
-                (
-                    Instruction::load_boolean(Destination::Register(1), false, false),
-                    Type::Boolean,
-                    Span(8, 13)
-                ),
-                (Instruction::r#return(true), Type::None, Span(13, 13)),
-            ],
-            vec![],
-            vec![]
-        ))
-    );
-
-    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(true))));
-}
-
-#[test]
-fn and_and_or() {
-    let source = "let a = true; let b = true; let c = false; a && b || c";
-
-    assert_eq!(
-        compile(source),
-        Ok(Chunk::with_data(
-            None,
-            FunctionType {
-                type_parameters: None,
-                value_parameters: None,
-                return_type: Box::new(Type::Boolean),
-            },
-            vec![
-                (
-                    Instruction::load_boolean(Destination::Register(0), true, false),
-                    Type::Boolean,
-                    Span(8, 12)
-                ),
-                (
-                    Instruction::define_local(0, 0, false),
-                    Type::None,
-                    Span(4, 5)
-                ),
-                (
-                    Instruction::load_boolean(Destination::Register(1), true, false),
-                    Type::Boolean,
-                    Span(22, 26)
-                ),
-                (
-                    Instruction::define_local(1, 1, false),
-                    Type::None,
-                    Span(18, 19)
-                ),
-                (
-                    Instruction::load_boolean(Destination::Register(2), false, false),
-                    Type::Boolean,
-                    Span(36, 41)
-                ),
-                (
-                    Instruction::define_local(2, 2, false),
-                    Type::None,
-                    Span(32, 33)
-                ),
-                (
-                    Instruction::test(Argument::Local(0), true),
-                    Type::None,
-                    Span(45, 47)
-                ),
-                (Instruction::jump(1, true), Type::None, Span(45, 47)),
-                (
-                    Instruction::test(Argument::Local(1), false),
-                    Type::None,
-                    Span(50, 52)
-                ),
-                (Instruction::jump(1, true), Type::None, Span(50, 52)),
-                (
-                    Instruction::get_local(Destination::Register(3), 2),
-                    Type::Boolean,
-                    Span(53, 54)
-                ),
-                (Instruction::r#return(true), Type::None, Span(54, 54)),
-            ],
-            vec![
-                ConcreteValue::string("a"),
-                ConcreteValue::string("b"),
-                ConcreteValue::string("c")
-            ],
-            vec![
-                Local::new(0, Type::Boolean, false, Scope::default()),
-                Local::new(1, Type::Boolean, false, Scope::default()),
-                Local::new(2, Type::Boolean, false, Scope::default())
-            ]
-        ))
-    );
-
-    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(true))));
-}
diff --git a/dust-lang/tests/logic_booleans.rs b/dust-lang/tests/logic_booleans.rs
new file mode 100644
index 0000000..ca5b635
--- /dev/null
+++ b/dust-lang/tests/logic_booleans.rs
@@ -0,0 +1,69 @@
+use dust_lang::*;
+
+#[test]
+fn and() {
+    let source = "true && false";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), true, false),
+                    Span(0, 4)
+                ),
+                (Instruction::test(Argument::Register(0), true), Span(5, 7)),
+                (Instruction::jump(1, true), Span(5, 7)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), false, false),
+                    Span(8, 13)
+                ),
+                (Instruction::r#return(true), Span(13, 13)),
+            ],
+            vec![],
+            vec![]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(false))));
+}
+
+#[test]
+fn or() {
+    let source = "true || false";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), true, false),
+                    Span(0, 4)
+                ),
+                (Instruction::test(Argument::Register(0), false), Span(5, 7)),
+                (Instruction::jump(1, true), Span(5, 7)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), false, false),
+                    Span(8, 13)
+                ),
+                (Instruction::r#return(true), Span(13, 13)),
+            ],
+            vec![],
+            vec![]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(true))));
+}
diff --git a/dust-lang/tests/logic_variables.rs b/dust-lang/tests/logic_variables.rs
new file mode 100644
index 0000000..e2519c8
--- /dev/null
+++ b/dust-lang/tests/logic_variables.rs
@@ -0,0 +1,378 @@
+use dust_lang::*;
+
+#[test]
+fn true_and_true() {
+    let source = "let a = true; let b = true; a && b";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), true, false),
+                    Span(8, 12)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), true, false),
+                    Span(22, 26)
+                ),
+                (Instruction::define_local(1, 1, false), Span(18, 19)),
+                (
+                    Instruction::get_local(Destination::Register(2), 0),
+                    Span(28, 29)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(30, 32)),
+                (Instruction::jump(1, true), Span(30, 32)),
+                (
+                    Instruction::get_local(Destination::Register(3), 1),
+                    Span(33, 34)
+                ),
+                (Instruction::r#return(true), Span(34, 34)),
+            ],
+            vec![ConcreteValue::string("a"), ConcreteValue::string("b")],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(true))));
+}
+
+#[test]
+fn false_and_false() {
+    let source = "let a = false; let b = false; a && b";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), false, false),
+                    Span(8, 13)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), false, false),
+                    Span(23, 28)
+                ),
+                (Instruction::define_local(1, 1, false), Span(19, 20)),
+                (
+                    Instruction::get_local(Destination::Register(2), 0),
+                    Span(30, 31)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(32, 34)),
+                (Instruction::jump(1, true), Span(32, 34)),
+                (
+                    Instruction::get_local(Destination::Register(3), 1),
+                    Span(35, 36)
+                ),
+                (Instruction::r#return(true), Span(36, 36)),
+            ],
+            vec![ConcreteValue::string("a"), ConcreteValue::string("b")],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(false))));
+}
+
+#[test]
+fn true_and_false() {
+    let source = "let a = true; let b = false; a && b";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), true, false),
+                    Span(8, 12)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), false, false),
+                    Span(22, 27)
+                ),
+                (Instruction::define_local(1, 1, false), Span(18, 19)),
+                (
+                    Instruction::get_local(Destination::Register(2), 0),
+                    Span(29, 30)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(31, 33)),
+                (Instruction::jump(1, true), Span(31, 33)),
+                (
+                    Instruction::get_local(Destination::Register(3), 1),
+                    Span(34, 35)
+                ),
+                (Instruction::r#return(true), Span(35, 35)),
+            ],
+            vec![ConcreteValue::string("a"), ConcreteValue::string("b")],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(false))));
+}
+
+#[test]
+fn false_and_true() {
+    let source = "let a = false; let b = true; a && b";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), false, false),
+                    Span(8, 13)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), true, false),
+                    Span(23, 27)
+                ),
+                (Instruction::define_local(1, 1, false), Span(19, 20)),
+                (
+                    Instruction::get_local(Destination::Register(2), 0),
+                    Span(29, 30)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(31, 33)),
+                (Instruction::jump(1, true), Span(31, 33)),
+                (
+                    Instruction::get_local(Destination::Register(3), 1),
+                    Span(34, 35)
+                ),
+                (Instruction::r#return(true), Span(35, 35)),
+            ],
+            vec![ConcreteValue::string("a"), ConcreteValue::string("b")],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(false))));
+}
+
+#[test]
+fn true_and_true_and_true() {
+    let source = "let a = true; let b = true; let c = true; a && b && c";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), true, false),
+                    Span(8, 12)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), true, false),
+                    Span(22, 26)
+                ),
+                (Instruction::define_local(1, 1, false), Span(18, 19)),
+                (
+                    Instruction::load_boolean(Destination::Register(2), true, false),
+                    Span(36, 40)
+                ),
+                (Instruction::define_local(2, 2, false), Span(32, 33)),
+                (
+                    Instruction::get_local(Destination::Register(3), 0),
+                    Span(42, 43)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(44, 46)),
+                (Instruction::jump(1, true), Span(44, 46)),
+                (
+                    Instruction::get_local(Destination::Register(4), 1),
+                    Span(47, 48)
+                ),
+                (Instruction::test(Argument::Local(1), true), Span(49, 51)),
+                (Instruction::jump(1, true), Span(49, 51)),
+                (
+                    Instruction::get_local(Destination::Register(5), 2),
+                    Span(52, 53)
+                ),
+                (Instruction::r#return(true), Span(53, 53)),
+            ],
+            vec![
+                ConcreteValue::string("a"),
+                ConcreteValue::string("b"),
+                ConcreteValue::string("c")
+            ],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default()),
+                Local::new(2, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(true))));
+}
+
+#[test]
+fn false_and_false_and_false() {
+    let source = "let a = false; let b = false; let c = false; a && b && c";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), false, false),
+                    Span(8, 13)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), false, false),
+                    Span(23, 28)
+                ),
+                (Instruction::define_local(1, 1, false), Span(19, 20)),
+                (
+                    Instruction::load_boolean(Destination::Register(2), false, false),
+                    Span(38, 43)
+                ),
+                (Instruction::define_local(2, 2, false), Span(34, 35)),
+                (
+                    Instruction::get_local(Destination::Register(3), 0),
+                    Span(45, 46)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(47, 49)),
+                (Instruction::jump(1, true), Span(47, 49)),
+                (
+                    Instruction::get_local(Destination::Register(4), 1),
+                    Span(50, 51)
+                ),
+                (Instruction::test(Argument::Local(1), true), Span(52, 54)),
+                (Instruction::jump(1, true), Span(52, 54)),
+                (
+                    Instruction::get_local(Destination::Register(5), 2),
+                    Span(55, 56)
+                ),
+                (Instruction::r#return(true), Span(56, 56)),
+            ],
+            vec![
+                ConcreteValue::string("a"),
+                ConcreteValue::string("b"),
+                ConcreteValue::string("c")
+            ],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default()),
+                Local::new(2, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(false))));
+}
+
+#[test]
+fn true_and_true_or_false() {
+    let source = "let a = true; let b = true; let c = false; a && b || c";
+
+    assert_eq!(
+        compile(source),
+        Ok(Chunk::with_data(
+            None,
+            FunctionType {
+                type_parameters: None,
+                value_parameters: None,
+                return_type: Box::new(Type::Boolean),
+            },
+            vec![
+                (
+                    Instruction::load_boolean(Destination::Register(0), true, false),
+                    Span(8, 12)
+                ),
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (
+                    Instruction::load_boolean(Destination::Register(1), true, false),
+                    Span(22, 26)
+                ),
+                (Instruction::define_local(1, 1, false), Span(18, 19)),
+                (
+                    Instruction::load_boolean(Destination::Register(2), false, false),
+                    Span(36, 41)
+                ),
+                (Instruction::define_local(2, 2, false), Span(32, 33)),
+                (
+                    Instruction::get_local(Destination::Register(3), 0),
+                    Span(43, 44)
+                ),
+                (Instruction::test(Argument::Local(0), true), Span(45, 47)),
+                (Instruction::jump(1, true), Span(45, 47)),
+                (
+                    Instruction::get_local(Destination::Register(4), 1),
+                    Span(48, 49)
+                ),
+                (Instruction::test(Argument::Local(1), false), Span(50, 52)),
+                (Instruction::jump(1, true), Span(50, 52)),
+                (
+                    Instruction::get_local(Destination::Register(5), 2),
+                    Span(53, 54)
+                ),
+                (Instruction::r#return(true), Span(54, 54)),
+            ],
+            vec![
+                ConcreteValue::string("a"),
+                ConcreteValue::string("b"),
+                ConcreteValue::string("c")
+            ],
+            vec![
+                Local::new(0, Type::Boolean, false, Scope::default()),
+                Local::new(1, Type::Boolean, false, Scope::default()),
+                Local::new(2, Type::Boolean, false, Scope::default())
+            ]
+        ))
+    );
+
+    assert_eq!(run(source), Ok(Some(ConcreteValue::Boolean(true))));
+}
diff --git a/dust-lang/tests/loops.rs b/dust-lang/tests/loops.rs
index 2ca09aa..c8bbbf4 100644
--- a/dust-lang/tests/loops.rs
+++ b/dust-lang/tests/loops.rs
@@ -16,36 +16,28 @@ fn r#while() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(12, 13)
                 ),
-                (
-                    Instruction::define_local(0, 0, true),
-                    Type::None,
-                    Span(8, 9)
-                ),
+                (Instruction::define_local(0, 0, true), Span(8, 9)),
                 (
                     Instruction::less(true, Argument::Local(0), Argument::Constant(2)),
-                    Type::None,
                     Span(23, 24)
                 ),
-                (Instruction::jump(2, true), Type::None, Span(41, 42)),
+                (Instruction::jump(2, true), Span(41, 42)),
                 (
                     Instruction::add(
                         Destination::Local(0),
                         Argument::Local(0),
                         Argument::Constant(3)
                     ),
-                    Type::Integer,
                     Span(35, 36)
                 ),
-                (Instruction::jump(3, false), Type::None, Span(41, 42)),
+                (Instruction::jump(3, false), Span(41, 42)),
                 (
                     Instruction::get_local(Destination::Register(1), 0),
-                    Type::Integer,
                     Span(41, 42)
                 ),
-                (Instruction::r#return(true), Type::None, Span(42, 42)),
+                (Instruction::r#return(true), Span(42, 42)),
             ],
             vec![
                 ConcreteValue::Integer(0),
diff --git a/dust-lang/tests/math.rs b/dust-lang/tests/math.rs
index f17fe8c..34b8256 100644
--- a/dust-lang/tests/math.rs
+++ b/dust-lang/tests/math.rs
@@ -20,10 +20,9 @@ fn add() {
                         Argument::Constant(0),
                         Argument::Constant(1)
                     ),
-                    Type::Integer,
                     Span(2, 3)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5))
+                (Instruction::r#return(true), Span(5, 5))
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -49,29 +48,22 @@ fn add_assign() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(12, 13)
                 ),
-                (
-                    Instruction::define_local(0, 0, true),
-                    Type::None,
-                    Span(8, 9)
-                ),
+                (Instruction::define_local(0, 0, true), Span(8, 9)),
                 (
                     Instruction::add(
                         Destination::Local(0),
                         Argument::Local(0),
                         Argument::Constant(2)
                     ),
-                    Type::None,
                     Span(17, 19)
                 ),
                 (
                     Instruction::get_local(Destination::Register(1), 0),
-                    Type::Integer,
                     Span(23, 24)
                 ),
-                (Instruction::r#return(true), Type::None, Span(24, 24))
+                (Instruction::r#return(true), Span(24, 24))
             ],
             vec![
                 ConcreteValue::Integer(1),
@@ -137,10 +129,9 @@ fn divide() {
                         Argument::Constant(0),
                         Argument::Constant(0)
                     ),
-                    Type::Integer,
                     Span(2, 3)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5))
+                (Instruction::r#return(true), Span(5, 5))
             ],
             vec![ConcreteValue::Integer(2)],
             vec![]
@@ -166,29 +157,22 @@ fn divide_assign() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(12, 13)
                 ),
-                (
-                    Instruction::define_local(0, 0, true),
-                    Type::None,
-                    Span(8, 9)
-                ),
+                (Instruction::define_local(0, 0, true), Span(8, 9)),
                 (
                     Instruction::divide(
                         Destination::Local(0),
                         Argument::Local(0),
                         Argument::Constant(0)
                     ),
-                    Type::None,
                     Span(17, 19)
                 ),
                 (
                     Instruction::get_local(Destination::Register(1), 0),
-                    Type::Integer,
                     Span(23, 24)
                 ),
-                (Instruction::r#return(true), Type::None, Span(24, 24))
+                (Instruction::r#return(true), Span(24, 24))
             ],
             vec![ConcreteValue::Integer(2), ConcreteValue::string("a")],
             vec![Local::new(1, Type::Integer, true, Scope::default())]
@@ -234,7 +218,6 @@ fn math_operator_precedence() {
                         Argument::Constant(0),
                         Argument::Constant(1)
                     ),
-                    Type::Integer,
                     Span(2, 3)
                 ),
                 (
@@ -243,7 +226,6 @@ fn math_operator_precedence() {
                         Argument::Constant(2),
                         Argument::Constant(3)
                     ),
-                    Type::Integer,
                     Span(10, 11)
                 ),
                 (
@@ -252,7 +234,6 @@ fn math_operator_precedence() {
                         Argument::Register(1),
                         Argument::Constant(4)
                     ),
-                    Type::Integer,
                     Span(14, 15)
                 ),
                 (
@@ -261,10 +242,9 @@ fn math_operator_precedence() {
                         Argument::Register(0),
                         Argument::Register(2)
                     ),
-                    Type::Integer,
                     Span(6, 7)
                 ),
-                (Instruction::r#return(true), Type::None, Span(17, 17)),
+                (Instruction::r#return(true), Span(17, 17)),
             ],
             vec![
                 ConcreteValue::Integer(1),
@@ -300,10 +280,9 @@ fn multiply() {
                         Argument::Constant(0),
                         Argument::Constant(1)
                     ),
-                    Type::Integer,
                     Span(2, 3)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5)),
+                (Instruction::r#return(true), Span(5, 5)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -329,29 +308,22 @@ fn multiply_assign() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(12, 13)
                 ),
-                (
-                    Instruction::define_local(0, 0, true),
-                    Type::None,
-                    Span(8, 9)
-                ),
+                (Instruction::define_local(0, 0, true), Span(8, 9)),
                 (
                     Instruction::multiply(
                         Destination::Local(0),
                         Argument::Local(0),
                         Argument::Constant(2)
                     ),
-                    Type::None,
                     Span(17, 19)
                 ),
                 (
                     Instruction::get_local(Destination::Register(1), 0),
-                    Type::Integer,
                     Span(22, 23)
                 ),
-                (Instruction::r#return(true), Type::None, Span(23, 23))
+                (Instruction::r#return(true), Span(23, 23))
             ],
             vec![
                 ConcreteValue::Integer(2),
@@ -401,10 +373,9 @@ fn subtract() {
                         Argument::Constant(0),
                         Argument::Constant(1)
                     ),
-                    Type::Integer,
                     Span(2, 3)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5)),
+                (Instruction::r#return(true), Span(5, 5)),
             ],
             vec![ConcreteValue::Integer(1), ConcreteValue::Integer(2)],
             vec![]
@@ -430,29 +401,22 @@ fn subtract_assign() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(12, 14)
                 ),
-                (
-                    Instruction::define_local(0, 0, true),
-                    Type::None,
-                    Span(8, 9)
-                ),
+                (Instruction::define_local(0, 0, true), Span(8, 9)),
                 (
                     Instruction::subtract(
                         Destination::Local(0),
                         Argument::Local(0),
                         Argument::Constant(2)
                     ),
-                    Type::None,
                     Span(18, 20)
                 ),
                 (
                     Instruction::get_local(Destination::Register(1), 0),
-                    Type::Integer,
                     Span(24, 25)
                 ),
-                (Instruction::r#return(true), Type::None, Span(25, 25)),
+                (Instruction::r#return(true), Span(25, 25)),
             ],
             vec![
                 ConcreteValue::Integer(42),
diff --git a/dust-lang/tests/native_functions.rs b/dust-lang/tests/native_functions.rs
index 4b83b21..abdc8b5 100644
--- a/dust-lang/tests/native_functions.rs
+++ b/dust-lang/tests/native_functions.rs
@@ -16,20 +16,17 @@ fn panic() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::String,
                     Span(6, 22)
                 ),
                 (
                     Instruction::load_constant(Destination::Register(1), 1, false),
-                    Type::Integer,
                     Span(24, 26)
                 ),
                 (
                     Instruction::call_native(Destination::Register(2), NativeFunction::Panic, 2),
-                    Type::None,
                     Span(0, 27)
                 ),
-                (Instruction::r#return(false), Type::None, Span(27, 27))
+                (Instruction::r#return(false), Span(27, 27))
             ],
             vec![
                 ConcreteValue::string("Goodbye world!"),
@@ -67,15 +64,13 @@ fn to_string() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(10, 12)
                 ),
                 (
                     Instruction::call_native(Destination::Register(1), NativeFunction::ToString, 1),
-                    Type::String,
                     Span(0, 13)
                 ),
-                (Instruction::r#return(true), Type::None, Span(13, 13))
+                (Instruction::r#return(true), Span(13, 13))
             ],
             vec![ConcreteValue::Integer(42)],
             vec![]
diff --git a/dust-lang/tests/scopes.rs b/dust-lang/tests/scopes.rs
index c34d33b..4bdc46b 100644
--- a/dust-lang/tests/scopes.rs
+++ b/dust-lang/tests/scopes.rs
@@ -38,55 +38,30 @@ fn block_scope() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(17, 18)
                 ),
-                (
-                    Instruction::define_local(0, 0, false),
-                    Type::None,
-                    Span(13, 14)
-                ),
+                (Instruction::define_local(0, 0, false), Span(13, 14)),
                 (
                     Instruction::load_constant(Destination::Register(1), 2, false),
-                    Type::Integer,
                     Span(50, 52)
                 ),
-                (
-                    Instruction::define_local(1, 1, false),
-                    Type::None,
-                    Span(46, 47)
-                ),
+                (Instruction::define_local(1, 1, false), Span(46, 47)),
                 (
                     Instruction::load_constant(Destination::Register(2), 4, false),
-                    Type::Integer,
                     Span(92, 93)
                 ),
-                (
-                    Instruction::define_local(2, 2, false),
-                    Type::None,
-                    Span(88, 89)
-                ),
+                (Instruction::define_local(2, 2, false), Span(88, 89)),
                 (
                     Instruction::load_constant(Destination::Register(3), 6, false),
-                    Type::Integer,
                     Span(129, 130)
                 ),
-                (
-                    Instruction::define_local(3, 3, false),
-                    Type::None,
-                    Span(125, 126)
-                ),
+                (Instruction::define_local(3, 3, false), Span(125, 126)),
                 (
                     Instruction::load_constant(Destination::Register(4), 4, false),
-                    Type::Integer,
                     Span(158, 159)
                 ),
-                (
-                    Instruction::define_local(4, 4, false),
-                    Type::None,
-                    Span(154, 155)
-                ),
-                (Instruction::r#return(false), Type::None, Span(165, 165))
+                (Instruction::define_local(4, 4, false), Span(154, 155)),
+                (Instruction::r#return(false), Span(165, 165))
             ],
             vec![
                 ConcreteValue::Integer(0),
@@ -146,95 +121,50 @@ fn multiple_block_scopes() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(17, 18)
                 ),
-                (
-                    Instruction::define_local(0, 0, false),
-                    Type::None,
-                    Span(13, 14)
-                ),
+                (Instruction::define_local(0, 0, false), Span(13, 14)),
                 (
                     Instruction::load_constant(Destination::Register(1), 2, false),
-                    Type::Integer,
                     Span(50, 52)
                 ),
-                (
-                    Instruction::define_local(1, 1, false),
-                    Type::None,
-                    Span(46, 47)
-                ),
+                (Instruction::define_local(1, 1, false), Span(46, 47)),
                 (
                     Instruction::load_constant(Destination::Register(2), 4, false),
-                    Type::Integer,
                     Span(92, 93)
                 ),
-                (
-                    Instruction::define_local(2, 2, false),
-                    Type::None,
-                    Span(88, 89)
-                ),
+                (Instruction::define_local(2, 2, false), Span(88, 89)),
                 (
                     Instruction::get_local(Destination::Register(3), 1),
-                    Type::Integer,
                     Span(129, 130)
                 ),
-                (
-                    Instruction::define_local(3, 3, false),
-                    Type::None,
-                    Span(125, 126)
-                ),
+                (Instruction::define_local(3, 3, false), Span(125, 126)),
                 (
                     Instruction::get_local(Destination::Register(4), 0),
-                    Type::Integer,
                     Span(158, 159)
                 ),
-                (
-                    Instruction::define_local(4, 4, false),
-                    Type::None,
-                    Span(154, 155)
-                ),
+                (Instruction::define_local(4, 4, false), Span(154, 155)),
                 (
                     Instruction::load_constant(Destination::Register(5), 2, false),
-                    Type::Integer,
                     Span(191, 193)
                 ),
-                (
-                    Instruction::define_local(5, 5, false),
-                    Type::None,
-                    Span(187, 188)
-                ),
+                (Instruction::define_local(5, 5, false), Span(187, 188)),
                 (
                     Instruction::load_constant(Destination::Register(6), 4, false),
-                    Type::Integer,
                     Span(233, 234)
                 ),
-                (
-                    Instruction::define_local(6, 6, false),
-                    Type::None,
-                    Span(229, 230)
-                ),
+                (Instruction::define_local(6, 6, false), Span(229, 230)),
                 (
                     Instruction::get_local(Destination::Register(7), 5),
-                    Type::Integer,
                     Span(270, 271)
                 ),
-                (
-                    Instruction::define_local(7, 7, false),
-                    Type::None,
-                    Span(266, 267)
-                ),
+                (Instruction::define_local(7, 7, false), Span(266, 267)),
                 (
                     Instruction::get_local(Destination::Register(8), 0),
-                    Type::Integer,
                     Span(299, 300)
                 ),
-                (
-                    Instruction::define_local(8, 8, false),
-                    Type::None,
-                    Span(295, 296)
-                ),
-                (Instruction::r#return(false), Type::None, Span(306, 306))
+                (Instruction::define_local(8, 8, false), Span(295, 296)),
+                (Instruction::r#return(false), Span(306, 306))
             ],
             vec![
                 ConcreteValue::Integer(0),
diff --git a/dust-lang/tests/unary_operations.rs b/dust-lang/tests/unary_operations.rs
index 8e289c5..f60f7d0 100644
--- a/dust-lang/tests/unary_operations.rs
+++ b/dust-lang/tests/unary_operations.rs
@@ -16,10 +16,9 @@ fn negate() {
             vec![
                 (
                     Instruction::negate(Destination::Register(0), Argument::Constant(0)),
-                    Type::Integer,
                     Span(0, 1)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5)),
+                (Instruction::r#return(true), Span(5, 5)),
             ],
             vec![ConcreteValue::Integer(42)],
             vec![]
@@ -45,15 +44,13 @@ fn not() {
             vec![
                 (
                     Instruction::load_boolean(Destination::Register(0), true, false),
-                    Type::Boolean,
                     Span(1, 5)
                 ),
                 (
                     Instruction::not(Destination::Register(1), Argument::Register(0)),
-                    Type::Boolean,
                     Span(0, 1)
                 ),
-                (Instruction::r#return(true), Type::None, Span(5, 5)),
+                (Instruction::r#return(true), Span(5, 5)),
             ],
             vec![],
             vec![]
diff --git a/dust-lang/tests/variables.rs b/dust-lang/tests/variables.rs
index bdd7254..ab83450 100644
--- a/dust-lang/tests/variables.rs
+++ b/dust-lang/tests/variables.rs
@@ -16,15 +16,10 @@ fn define_local() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(8, 10)
                 ),
-                (
-                    Instruction::define_local(0, 0, false),
-                    Type::None,
-                    Span(4, 5)
-                ),
-                (Instruction::r#return(false), Type::None, Span(11, 11))
+                (Instruction::define_local(0, 0, false), Span(4, 5)),
+                (Instruction::r#return(false), Span(11, 11))
             ],
             vec![ConcreteValue::Integer(42), ConcreteValue::string("x")],
             vec![Local::new(1, Type::Integer, false, Scope::default())]
@@ -67,26 +62,19 @@ fn set_local() {
             vec![
                 (
                     Instruction::load_constant(Destination::Register(0), 0, false),
-                    Type::Integer,
                     Span(12, 14)
                 ),
-                (
-                    Instruction::define_local(0, 0, true),
-                    Type::None,
-                    Span(8, 9)
-                ),
+                (Instruction::define_local(0, 0, true), Span(8, 9)),
                 (
                     Instruction::load_constant(Destination::Register(1), 2, false),
-                    Type::Integer,
                     Span(20, 22)
                 ),
-                (Instruction::set_local(1, 0), Type::None, Span(16, 17)),
+                (Instruction::set_local(1, 0), Span(16, 17)),
                 (
                     Instruction::get_local(Destination::Register(2), 0),
-                    Type::Integer,
                     Span(24, 25)
                 ),
-                (Instruction::r#return(true), Type::None, Span(25, 25)),
+                (Instruction::r#return(true), Span(25, 25)),
             ],
             vec![
                 ConcreteValue::Integer(41),