diff --git a/nac3core/src/typecheck/magic_methods.rs b/nac3core/src/typecheck/magic_methods.rs
index d25fff5..a11705f 100644
--- a/nac3core/src/typecheck/magic_methods.rs
+++ b/nac3core/src/typecheck/magic_methods.rs
@@ -90,7 +90,7 @@ pub fn impl_binop(
     _store: &PrimitiveStore,
     ty: Type,
     other_ty: &[Type],
-    ret_ty: Type,
+    ret_ty: Option<Type>,
     ops: &[Operator],
 ) {
     with_fields(unifier, ty, |unifier, fields| {
@@ -107,6 +107,8 @@ pub fn impl_binop(
             VarMap::new()
         };
 
+        let ret_ty = ret_ty.unwrap_or_else(|| unifier.get_fresh_var(None, None).0);
+
         for op in ops {
             fields.insert(binop_name(op).into(), {
                 (
@@ -141,8 +143,10 @@ pub fn impl_binop(
     });
 }
 
-pub fn impl_unaryop(unifier: &mut Unifier, ty: Type, ret_ty: Type, ops: &[Unaryop]) {
+pub fn impl_unaryop(unifier: &mut Unifier, ty: Type, ret_ty: Option<Type>, ops: &[Unaryop]) {
     with_fields(unifier, ty, |unifier, fields| {
+        let ret_ty = ret_ty.unwrap_or_else(|| unifier.get_fresh_var(None, None).0);
+
         for op in ops {
             fields.insert(
                 unaryop_name(op).into(),
@@ -161,19 +165,35 @@ pub fn impl_unaryop(unifier: &mut Unifier, ty: Type, ret_ty: Type, ops: &[Unaryo
 
 pub fn impl_cmpop(
     unifier: &mut Unifier,
-    store: &PrimitiveStore,
+    _store: &PrimitiveStore,
     ty: Type,
-    other_ty: Type,
+    other_ty: &[Type],
     ops: &[Cmpop],
+    ret_ty: Option<Type>,
 ) {
     with_fields(unifier, ty, |unifier, fields| {
+        let (other_ty, other_var_id) = if other_ty.len() == 1 {
+            (other_ty[0], None)
+        } else {
+            let (ty, var_id) = unifier.get_fresh_var_with_range(other_ty, Some("N".into()), None);
+            (ty, Some(var_id))
+        };
+
+        let function_vars = if let Some(var_id) = other_var_id {
+            vec![(var_id, other_ty)].into_iter().collect::<VarMap>()
+        } else {
+            VarMap::new()
+        };
+
+        let ret_ty = ret_ty.unwrap_or_else(|| unifier.get_fresh_var(None, None).0);
+
         for op in ops {
             fields.insert(
                 comparison_name(op).unwrap().into(),
                 (
                     unifier.add_ty(TypeEnum::TFunc(FunSignature {
-                        ret: store.bool,
-                        vars: VarMap::new(),
+                        ret: ret_ty,
+                        vars: function_vars.clone(),
                         args: vec![FuncArg {
                             ty: other_ty,
                             default_value: None,
@@ -193,7 +213,7 @@ pub fn impl_basic_arithmetic(
     store: &PrimitiveStore,
     ty: Type,
     other_ty: &[Type],
-    ret_ty: Type,
+    ret_ty: Option<Type>,
 ) {
     impl_binop(
         unifier,
@@ -211,7 +231,7 @@ pub fn impl_pow(
     store: &PrimitiveStore,
     ty: Type,
     other_ty: &[Type],
-    ret_ty: Type,
+    ret_ty: Option<Type>,
 ) {
     impl_binop(unifier, store, ty, other_ty, ret_ty, &[Operator::Pow]);
 }
@@ -223,19 +243,25 @@ pub fn impl_bitwise_arithmetic(unifier: &mut Unifier, store: &PrimitiveStore, ty
         store,
         ty,
         &[ty],
-        ty,
+        Some(ty),
         &[Operator::BitAnd, Operator::BitOr, Operator::BitXor],
     );
 }
 
 /// `LShift`, `RShift`
 pub fn impl_bitwise_shift(unifier: &mut Unifier, store: &PrimitiveStore, ty: Type) {
-    impl_binop(unifier, store, ty, &[store.int32, store.uint32], ty, &[Operator::LShift, Operator::RShift]);
+    impl_binop(unifier, store, ty, &[store.int32, store.uint32], Some(ty), &[Operator::LShift, Operator::RShift]);
 }
 
 /// `Div`
-pub fn impl_div(unifier: &mut Unifier, store: &PrimitiveStore, ty: Type, other_ty: &[Type]) {
-    impl_binop(unifier, store, ty, other_ty, store.float, &[Operator::Div]);
+pub fn impl_div(
+    unifier: &mut Unifier,
+    store: &PrimitiveStore,
+    ty: Type,
+    other_ty: &[Type],
+    ret_ty: Option<Type>,
+) {
+    impl_binop(unifier, store, ty, other_ty, ret_ty, &[Operator::Div]);
 }
 
 /// `FloorDiv`
@@ -244,7 +270,7 @@ pub fn impl_floordiv(
     store: &PrimitiveStore,
     ty: Type,
     other_ty: &[Type],
-    ret_ty: Type,
+    ret_ty: Option<Type>,
 ) {
     impl_binop(unifier, store, ty, other_ty, ret_ty, &[Operator::FloorDiv]);
 }
@@ -255,40 +281,53 @@ pub fn impl_mod(
     store: &PrimitiveStore,
     ty: Type,
     other_ty: &[Type],
-    ret_ty: Type,
+    ret_ty: Option<Type>,
 ) {
     impl_binop(unifier, store, ty, other_ty, ret_ty, &[Operator::Mod]);
 }
 
 /// `UAdd`, `USub`
-pub fn impl_sign(unifier: &mut Unifier, _store: &PrimitiveStore, ty: Type) {
-    impl_unaryop(unifier, ty, ty, &[Unaryop::UAdd, Unaryop::USub]);
+pub fn impl_sign(unifier: &mut Unifier, _store: &PrimitiveStore, ty: Type, ret_ty: Option<Type>) {
+    impl_unaryop(unifier, ty, ret_ty, &[Unaryop::UAdd, Unaryop::USub]);
 }
 
 /// `Invert`
-pub fn impl_invert(unifier: &mut Unifier, _store: &PrimitiveStore, ty: Type) {
-    impl_unaryop(unifier, ty, ty, &[Unaryop::Invert]);
+pub fn impl_invert(unifier: &mut Unifier, _store: &PrimitiveStore, ty: Type, ret_ty: Option<Type>) {
+    impl_unaryop(unifier, ty, ret_ty, &[Unaryop::Invert]);
 }
 
 /// `Not`
-pub fn impl_not(unifier: &mut Unifier, store: &PrimitiveStore, ty: Type) {
-    impl_unaryop(unifier, ty, store.bool, &[Unaryop::Not]);
+pub fn impl_not(unifier: &mut Unifier, _store: &PrimitiveStore, ty: Type, ret_ty: Option<Type>) {
+    impl_unaryop(unifier, ty, ret_ty, &[Unaryop::Not]);
 }
 
 /// `Lt`, `LtE`, `Gt`, `GtE`
-pub fn impl_comparison(unifier: &mut Unifier, store: &PrimitiveStore, ty: Type, other_ty: Type) {
+pub fn impl_comparison(
+    unifier: &mut Unifier,
+    store: &PrimitiveStore,
+    ty: Type,
+    other_ty: &[Type],
+    ret_ty: Option<Type>,
+) {
     impl_cmpop(
         unifier,
         store,
         ty,
         other_ty,
         &[Cmpop::Lt, Cmpop::Gt, Cmpop::LtE, Cmpop::GtE],
+        ret_ty,
     );
 }
 
 /// `Eq`, `NotEq`
-pub fn impl_eq(unifier: &mut Unifier, store: &PrimitiveStore, ty: Type) {
-    impl_cmpop(unifier, store, ty, ty, &[Cmpop::Eq, Cmpop::NotEq]);
+pub fn impl_eq(
+    unifier: &mut Unifier,
+    store: &PrimitiveStore,
+    ty: Type,
+    other_ty: &[Type],
+    ret_ty: Option<Type>,
+) {
+    impl_cmpop(unifier, store, ty, other_ty, &[Cmpop::Eq, Cmpop::NotEq], ret_ty);
 }
 
 pub fn set_primitives_magic_methods(store: &PrimitiveStore, unifier: &mut Unifier) {
@@ -304,34 +343,34 @@ pub fn set_primitives_magic_methods(store: &PrimitiveStore, unifier: &mut Unifie
 
     /* int ======== */
     for t in [int32_t, int64_t, uint32_t, uint64_t] {
-        impl_basic_arithmetic(unifier, store, t, &[t], t);
-        impl_pow(unifier, store, t, &[t], t);
+        impl_basic_arithmetic(unifier, store, t, &[t], Some(t));
+        impl_pow(unifier, store, t, &[t], Some(t));
         impl_bitwise_arithmetic(unifier, store, t);
         impl_bitwise_shift(unifier, store, t);
-        impl_div(unifier, store, t, &[t]);
-        impl_floordiv(unifier, store, t, &[t], t);
-        impl_mod(unifier, store, t, &[t], t);
-        impl_invert(unifier, store, t);
-        impl_not(unifier, store, t);
-        impl_comparison(unifier, store, t, t);
-        impl_eq(unifier, store, t);
+        impl_div(unifier, store, t, &[t], Some(float_t));
+        impl_floordiv(unifier, store, t, &[t], Some(t));
+        impl_mod(unifier, store, t, &[t], Some(t));
+        impl_invert(unifier, store, t, Some(t));
+        impl_not(unifier, store, t, Some(bool_t));
+        impl_comparison(unifier, store, t, &[t], Some(bool_t));
+        impl_eq(unifier, store, t, &[t], Some(bool_t));
     }
     for t in [int32_t, int64_t] {
-        impl_sign(unifier, store, t);
+        impl_sign(unifier, store, t, Some(t));
     }
 
     /* float ======== */
-    impl_basic_arithmetic(unifier, store, float_t, &[float_t], float_t);
-    impl_pow(unifier, store, float_t, &[int32_t, float_t], float_t);
-    impl_div(unifier, store, float_t, &[float_t]);
-    impl_floordiv(unifier, store, float_t, &[float_t], float_t);
-    impl_mod(unifier, store, float_t, &[float_t], float_t);
-    impl_sign(unifier, store, float_t);
-    impl_not(unifier, store, float_t);
-    impl_comparison(unifier, store, float_t, float_t);
-    impl_eq(unifier, store, float_t);
+    impl_basic_arithmetic(unifier, store, float_t, &[float_t], Some(float_t));
+    impl_pow(unifier, store, float_t, &[int32_t, float_t], Some(float_t));
+    impl_div(unifier, store, float_t, &[float_t], Some(float_t));
+    impl_floordiv(unifier, store, float_t, &[float_t], Some(float_t));
+    impl_mod(unifier, store, float_t, &[float_t], Some(float_t));
+    impl_sign(unifier, store, float_t, Some(float_t));
+    impl_not(unifier, store, float_t, Some(bool_t));
+    impl_comparison(unifier, store, float_t, &[float_t], Some(bool_t));
+    impl_eq(unifier, store, float_t, &[float_t], Some(bool_t));
 
     /* bool ======== */
-    impl_not(unifier, store, bool_t);
-    impl_eq(unifier, store, bool_t);
+    impl_not(unifier, store, bool_t, Some(bool_t));
+    impl_eq(unifier, store, bool_t, &[bool_t], Some(bool_t));
 }