diff --git a/crates/rue-compiler/src/compiler.rs b/crates/rue-compiler/src/compiler.rs
index 0126f23..f1d9e8e 100644
--- a/crates/rue-compiler/src/compiler.rs
+++ b/crates/rue-compiler/src/compiler.rs
@@ -164,7 +164,7 @@ impl<'a> Compiler<'a> {
                         })
                         .collect();
 
-                    format!("{{ {} }}", fields.join(", "))
+                    format!("{{{}}}", fields.join(", "))
                 } else {
                     self.type_name_visitor(struct_type.original_type_id, stack)
                 }
@@ -173,29 +173,31 @@ impl<'a> Compiler<'a> {
             Type::EnumVariant(enum_variant) => {
                 let enum_name = self.type_name_visitor(enum_variant.enum_type, stack);
 
-                let fields: Vec<String> = enum_variant
-                    .fields
-                    .iter()
-                    .map(|(name, ty)| format!("{}: {}", name, self.type_name_visitor(*ty, stack)))
-                    .collect();
+                let fields: Option<Vec<String>> = enum_variant.fields.as_ref().map(|fields| {
+                    fields
+                        .iter()
+                        .map(|(name, ty)| {
+                            format!("{}: {}", name, self.type_name_visitor(*ty, stack))
+                        })
+                        .collect()
+                });
 
-                format!(
-                    "{}::{} {{ {} }}",
-                    enum_name,
-                    match self.db.ty(enum_variant.enum_type) {
-                        Type::Enum(enum_type) => {
-                            enum_type
-                                .variants
-                                .iter()
-                                .find(|item| *item.1 == enum_variant.original_type_id)
-                                .expect("enum type is missing variant")
-                                .0
-                                .clone()
-                        }
-                        _ => unreachable!(),
-                    },
-                    fields.join(", ")
-                )
+                let variant_name = match self.db.ty(enum_variant.enum_type) {
+                    Type::Enum(enum_type) => enum_type
+                        .variants
+                        .iter()
+                        .find(|item| *item.1 == enum_variant.original_type_id)
+                        .expect("enum type is missing variant")
+                        .0
+                        .clone(),
+                    _ => unreachable!(),
+                };
+
+                if let Some(fields) = fields {
+                    format!("{enum_name}::{variant_name} {{{}}}", fields.join(", "))
+                } else {
+                    format!("{enum_name}::{variant_name}")
+                }
             }
             Type::Function(function_type) => {
                 let params: Vec<String> = function_type
diff --git a/crates/rue-compiler/src/compiler/expr/field_access_expr.rs b/crates/rue-compiler/src/compiler/expr/field_access_expr.rs
index 6442d18..b26f4fe 100644
--- a/crates/rue-compiler/src/compiler/expr/field_access_expr.rs
+++ b/crates/rue-compiler/src/compiler/expr/field_access_expr.rs
@@ -54,13 +54,12 @@ impl Compiler<'_> {
                 }
             }
             Type::EnumVariant(variant_type) => {
-                if let Some((index, _, &field_type)) =
-                    variant_type.fields.get_full(field_name.text())
-                {
+                let fields = variant_type.fields.unwrap_or_default();
+
+                if let Some((index, _, &field_type)) = fields.get_full(field_name.text()) {
                     let mut type_id = field_type;
 
-                    if index == variant_type.fields.len() - 1 && variant_type.rest == Rest::Optional
-                    {
+                    if index == fields.len() - 1 && variant_type.rest == Rest::Optional {
                         type_id = self.db.alloc_type(Type::PossiblyUndefined(type_id));
                     }
 
@@ -68,8 +67,7 @@ impl Compiler<'_> {
                         self.compile_index(
                             old_value.hir_id,
                             index,
-                            index == variant_type.fields.len() - 1
-                                && variant_type.rest == Rest::Spread,
+                            index == fields.len() - 1 && variant_type.rest == Rest::Spread,
                         ),
                         type_id,
                     )
diff --git a/crates/rue-compiler/src/compiler/expr/initializer_expr.rs b/crates/rue-compiler/src/compiler/expr/initializer_expr.rs
index d1052fb..d59ee0d 100644
--- a/crates/rue-compiler/src/compiler/expr/initializer_expr.rs
+++ b/crates/rue-compiler/src/compiler/expr/initializer_expr.rs
@@ -33,21 +33,29 @@ impl Compiler<'_> {
                 }
             }
             Some(Type::EnumVariant(enum_variant)) => {
-                let fields_hir_id = self.compile_initializer_fields(
-                    ty.unwrap(),
-                    &enum_variant.fields,
-                    enum_variant.rest,
-                    initializer.fields(),
-                    initializer.syntax().text_range(),
-                );
-
-                let hir_id = self
-                    .db
-                    .alloc_hir(Hir::Pair(enum_variant.discriminant, fields_hir_id));
-
-                match ty {
-                    Some(struct_type) => Value::new(hir_id, struct_type),
-                    None => self.unknown(),
+                if let Some(fields) = enum_variant.fields {
+                    let fields_hir_id = self.compile_initializer_fields(
+                        ty.unwrap(),
+                        &fields,
+                        enum_variant.rest,
+                        initializer.fields(),
+                        initializer.syntax().text_range(),
+                    );
+
+                    let hir_id = self
+                        .db
+                        .alloc_hir(Hir::Pair(enum_variant.discriminant, fields_hir_id));
+
+                    match ty {
+                        Some(struct_type) => Value::new(hir_id, struct_type),
+                        None => self.unknown(),
+                    }
+                } else {
+                    self.db.error(
+                        ErrorKind::EnumVariantWithoutFields,
+                        initializer.path().unwrap().syntax().text_range(),
+                    );
+                    self.unknown()
                 }
             }
             Some(_) => {
diff --git a/crates/rue-compiler/src/compiler/expr/path_expr.rs b/crates/rue-compiler/src/compiler/expr/path_expr.rs
index de8f7d0..753422b 100644
--- a/crates/rue-compiler/src/compiler/expr/path_expr.rs
+++ b/crates/rue-compiler/src/compiler/expr/path_expr.rs
@@ -33,14 +33,9 @@ impl Compiler<'_> {
             PathItem::Symbol(symbol_id) => symbol_id,
             PathItem::Type(type_id) => {
                 if let Type::EnumVariant(variant_type) = self.db.ty(type_id).clone() {
-                    let Type::Enum(enum_type) = self.db.ty(variant_type.enum_type) else {
-                        unreachable!();
-                    };
-
-                    if enum_type.has_fields {
+                    if variant_type.fields.is_some() {
                         self.db.error(ErrorKind::EnumVariantWithFields, text_range);
                     }
-
                     return Value::new(variant_type.discriminant, type_id);
                 }
                 self.db.error(ErrorKind::ExpectedSymbolPath, text_range);
diff --git a/crates/rue-compiler/src/compiler/item/enum_item.rs b/crates/rue-compiler/src/compiler/item/enum_item.rs
index 168a4c3..e3f6edb 100644
--- a/crates/rue-compiler/src/compiler/item/enum_item.rs
+++ b/crates/rue-compiler/src/compiler/item/enum_item.rs
@@ -148,7 +148,11 @@ impl Compiler<'_> {
             *self.db.ty_mut(variant_type_id) = Type::EnumVariant(EnumVariantType {
                 enum_type: enum_type_id,
                 original_type_id: variant_type_id,
-                fields,
+                fields: if variant.fields().is_some() {
+                    Some(fields)
+                } else {
+                    None
+                },
                 rest,
                 discriminant,
             });
diff --git a/crates/rue-compiler/src/database/type_system.rs b/crates/rue-compiler/src/database/type_system.rs
index 8c0fdf5..a08cdeb 100644
--- a/crates/rue-compiler/src/database/type_system.rs
+++ b/crates/rue-compiler/src/database/type_system.rs
@@ -137,16 +137,17 @@ impl Database {
                 let new_variant = EnumVariantType {
                     enum_type: enum_variant.enum_type,
                     original_type_id: enum_variant.original_type_id,
-                    fields: enum_variant
-                        .fields
-                        .iter()
-                        .map(|(k, v)| {
-                            (
-                                k.clone(),
-                                self.substitute_type_visitor(*v, substitutions, visited),
-                            )
-                        })
-                        .collect(),
+                    fields: enum_variant.fields.as_ref().map(|fields| {
+                        fields
+                            .iter()
+                            .map(|(k, v)| {
+                                (
+                                    k.clone(),
+                                    self.substitute_type_visitor(*v, substitutions, visited),
+                                )
+                            })
+                            .collect()
+                    }),
                     rest: enum_variant.rest,
                     discriminant: enum_variant.discriminant,
                 };
@@ -755,7 +756,7 @@ mod tests {
         *db.ty_mut(variant) = Type::EnumVariant(EnumVariantType {
             enum_type,
             original_type_id: variant,
-            fields: fields(&[ty.int]),
+            fields: Some(fields(&[ty.int])),
             discriminant: ty.unknown_hir,
             rest: Rest::Nil,
         });
diff --git a/crates/rue-compiler/src/error.rs b/crates/rue-compiler/src/error.rs
index 711109e..18a723b 100644
--- a/crates/rue-compiler/src/error.rs
+++ b/crates/rue-compiler/src/error.rs
@@ -188,9 +188,12 @@ pub enum ErrorKind {
     #[error("enum discriminant too large")]
     EnumDiscriminantTooLarge,
 
-    #[error("cannot reference enum variants of enums with fields")]
+    #[error("cannot directly reference enum variants with fields")]
     EnumVariantWithFields,
 
+    #[error("cannot initialize enum variants without fields")]
+    EnumVariantWithoutFields,
+
     #[error("unknown enum variant `{0}`")]
     UnknownEnumVariant(String),
 
diff --git a/crates/rue-compiler/src/value/ty.rs b/crates/rue-compiler/src/value/ty.rs
index 49b5c2b..640d662 100644
--- a/crates/rue-compiler/src/value/ty.rs
+++ b/crates/rue-compiler/src/value/ty.rs
@@ -47,7 +47,7 @@ pub struct EnumType {
 pub struct EnumVariantType {
     pub enum_type: TypeId,
     pub original_type_id: TypeId,
-    pub fields: IndexMap<String, TypeId>,
+    pub fields: Option<IndexMap<String, TypeId>>,
     pub rest: Rest,
     pub discriminant: HirId,
 }
diff --git a/std/stdlib.rue b/std/stdlib.rue
index 14a2b6a..e9f7d15 100644
--- a/std/stdlib.rue
+++ b/std/stdlib.rue
@@ -1,7 +1,7 @@
 
 export enum Condition {
     Remark = 1 {
-        // TODO: Optional value
+        value?: Any,
     },
     AggSigParent = 43 {
         public_key: PublicKey,
@@ -38,7 +38,7 @@ export enum Condition {
     CreateCoin = 51 {
         puzzle_hash: Bytes32,
         amount: Int,
-        // TODO: Optional memos
+        memos?: Bytes[],
     },
     ReserveFee = 52 {
         amount: Int,
@@ -79,9 +79,7 @@ export enum Condition {
     AssertMyBirthHeight = 75 {
         height: Int,
     },
-    AssertEphemeral = 76 {
-        // TODO: Unit variants and enum repr
-    },
+    AssertEphemeral = 76,
     AssertSecondsRelative = 80 {
         seconds: Int,
     },
@@ -108,7 +106,7 @@ export enum Condition {
     },
     Softfork = 90 {
         cost: Int,
-        // TODO: Rest args with type `Any`
+        value?: Any,
     },
 }
 
diff --git a/tests.toml b/tests.toml
index 1871e67..ceb1e21 100644
--- a/tests.toml
+++ b/tests.toml
@@ -364,3 +364,13 @@ input = "()"
 output = "()"
 hash = "42840c6aebec47ce2e01629ce381b461c19695264281a7b1aab5d4ff54506775"
 error = "()"
+
+[unit_variant]
+parser_errors = []
+compiler_errors = [
+    "unused let binding `non_unit` at 7:9",
+    "unused let binding `unit` at 8:9",
+    "unused enum variant `NonUnit` at 2:5",
+    "unused enum variant `Unit` at 3:5",
+    "unused enum `Enum` at 1:6",
+]
diff --git a/tests/types/unit_variant.rue b/tests/types/unit_variant.rue
new file mode 100644
index 0000000..bcc3b03
--- /dev/null
+++ b/tests/types/unit_variant.rue
@@ -0,0 +1,10 @@
+enum Enum {
+    NonUnit {},
+    Unit,
+}
+
+fun main() -> Int {
+    let non_unit = Enum::NonUnit {};
+    let unit = Enum::Unit;
+    0
+}