diff --git a/compiler/gen_llvm/src/llvm/build.rs b/compiler/gen_llvm/src/llvm/build.rs
index 815e636473..9100f2bc64 100644
--- a/compiler/gen_llvm/src/llvm/build.rs
+++ b/compiler/gen_llvm/src/llvm/build.rs
@@ -973,10 +973,9 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
         Tag {
             arguments,
             tag_layout: union_layout,
-            union_size,
             tag_id,
             ..
-        } => build_tag(env, scope, union_layout, *union_size, *tag_id, arguments),
+        } => build_tag(env, scope, union_layout, *tag_id, arguments),
 
         Reset(_) => todo!(),
         Reuse { .. } => todo!(),
@@ -1174,12 +1173,13 @@ pub fn build_tag<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
     scope: &Scope<'a, 'ctx>,
     union_layout: &UnionLayout<'a>,
-    union_size: u8,
     tag_id: u8,
     arguments: &[Symbol],
 ) -> BasicValueEnum<'ctx> {
     let tag_id_layout = union_layout.tag_id_layout();
 
+    let union_size = union_layout.number_of_tags();
+
     match union_layout {
         UnionLayout::NonRecursive(tags) => {
             debug_assert!(union_size > 1);
diff --git a/compiler/mono/src/alias_analysis.rs b/compiler/mono/src/alias_analysis.rs
index 2b4354d26e..a439cd62e0 100644
--- a/compiler/mono/src/alias_analysis.rs
+++ b/compiler/mono/src/alias_analysis.rs
@@ -836,7 +836,6 @@ fn expr_spec(
             tag_layout,
             tag_name: _,
             tag_id,
-            union_size: _,
             arguments,
         } => match tag_layout {
             UnionLayout::NonRecursive(_) => {
diff --git a/compiler/mono/src/ir.rs b/compiler/mono/src/ir.rs
index 94877e4ad0..9c8a498389 100644
--- a/compiler/mono/src/ir.rs
+++ b/compiler/mono/src/ir.rs
@@ -1129,7 +1129,6 @@ pub enum Expr<'a> {
         tag_layout: UnionLayout<'a>,
         tag_name: TagName,
         tag_id: u8,
-        union_size: u8,
         arguments: &'a [Symbol],
     },
     Struct(&'a [Symbol]),
@@ -1160,6 +1159,9 @@ pub enum Expr<'a> {
 
     Reuse {
         symbol: Symbol,
+        update_tag_id: bool,
+        // normal Tag fields
+        tag_layout: UnionLayout<'a>,
         tag_name: TagName,
         tag_id: u8,
         arguments: &'a [Symbol],
@@ -4031,14 +4033,12 @@ fn construct_closure_data<'a>(
         ClosureRepresentation::Union {
             tag_id,
             tag_layout: _,
-            union_size,
             tag_name,
             union_layout,
         } => {
             let expr = Expr::Tag {
                 tag_id,
                 tag_layout: union_layout,
-                union_size,
                 tag_name,
                 arguments: symbols,
             };
@@ -4167,7 +4167,6 @@ fn convert_tag_union<'a>(
             assign_to_symbols(env, procs, layout_cache, iter, stmt)
         }
         Wrapped(variant) => {
-            let union_size = variant.number_of_tags() as u8;
             let (tag_id, _) = variant.tag_name_to_id(&tag_name);
 
             let field_symbols_temp = sorted_field_symbols(env, procs, layout_cache, args);
@@ -4203,7 +4202,6 @@ fn convert_tag_union<'a>(
                         tag_layout: union_layout,
                         tag_name,
                         tag_id: tag_id as u8,
-                        union_size,
                         arguments: field_symbols,
                     };
 
@@ -4231,7 +4229,6 @@ fn convert_tag_union<'a>(
                         tag_layout: union_layout,
                         tag_name,
                         tag_id: tag_id as u8,
-                        union_size,
                         arguments: field_symbols,
                     };
 
@@ -4261,7 +4258,6 @@ fn convert_tag_union<'a>(
                         tag_layout: union_layout,
                         tag_name,
                         tag_id: tag_id as u8,
-                        union_size,
                         arguments: field_symbols,
                     };
 
@@ -4298,7 +4294,6 @@ fn convert_tag_union<'a>(
                         tag_layout: union_layout,
                         tag_name,
                         tag_id: tag_id as u8,
-                        union_size,
                         arguments: field_symbols,
                     };
 
@@ -4331,7 +4326,6 @@ fn convert_tag_union<'a>(
                         tag_layout: union_layout,
                         tag_name,
                         tag_id: tag_id as u8,
-                        union_size,
                         arguments: field_symbols,
                     };
 
@@ -5381,7 +5375,6 @@ fn substitute_in_expr<'a>(
             tag_layout,
             tag_name,
             tag_id,
-            union_size,
             arguments: args,
         } => {
             let mut did_change = false;
@@ -5403,7 +5396,6 @@ fn substitute_in_expr<'a>(
                     tag_layout: *tag_layout,
                     tag_name: tag_name.clone(),
                     tag_id: *tag_id,
-                    union_size: *union_size,
                     arguments,
                 })
             } else {
diff --git a/compiler/mono/src/layout.rs b/compiler/mono/src/layout.rs
index 6152b73304..89ea62d0b2 100644
--- a/compiler/mono/src/layout.rs
+++ b/compiler/mono/src/layout.rs
@@ -148,6 +148,16 @@ impl<'a> UnionLayout<'a> {
         }
     }
 
+    pub fn number_of_tags(&'a self) -> usize {
+        match self {
+            UnionLayout::NonRecursive(tags) | UnionLayout::Recursive(tags) => tags.len(),
+
+            UnionLayout::NullableWrapped { other_tags, .. } => other_tags.len() + 1,
+            UnionLayout::NonNullableUnwrapped(_) => 1,
+            UnionLayout::NullableUnwrapped { .. } => 2,
+        }
+    }
+
     fn tag_id_builtin_help(union_size: usize) -> Builtin<'a> {
         if union_size <= u8::MAX as usize {
             Builtin::Int8
@@ -204,7 +214,6 @@ pub enum ClosureRepresentation<'a> {
         tag_layout: &'a [Layout<'a>],
         tag_name: TagName,
         tag_id: u8,
-        union_size: u8,
         union_layout: UnionLayout<'a>,
     },
     /// the representation is anything but a union
@@ -243,7 +252,6 @@ impl<'a> LambdaSet<'a> {
                             .unwrap();
 
                         ClosureRepresentation::Union {
-                            union_size: self.set.len() as u8,
                             tag_id: index as u8,
                             tag_layout: tags[index],
                             tag_name: TagName::Closure(function_symbol),
diff --git a/compiler/mono/src/lib.rs b/compiler/mono/src/lib.rs
index 831ff3d8c1..9a79927aec 100644
--- a/compiler/mono/src/lib.rs
+++ b/compiler/mono/src/lib.rs
@@ -8,6 +8,7 @@ pub mod expand_rc;
 pub mod inc_dec;
 pub mod ir;
 pub mod layout;
+// pub mod reset_reuse;
 pub mod tail_recursion;
 
 // Temporary, while we can build up test cases and optimize the exhaustiveness checking.