src/Trait.ts

@@ -28,18 +28,27 @@ type RemoveAbstractFromImplClass<
 
 
 export class Trait<
-    Super     extends TraitExpression<typeof TraitExpressionNullSuperclass, Trait<any, any, any>[], Trait<any, any, any>[]>,
+    Supertraits extends TraitExpression<typeof TraitExpressionNullSuperclass, Trait<any, any, any>[], Trait<any, any, any>[]>,
     Abstract    extends {},
     ImplClass   extends Class<{}, []>,
 > {
     constructor(
-        readonly supertraits:  Super,
+        readonly supertraits:  Supertraits,
         readonly abstract:     Abstract,
         readonly apply:        (Super: AbstractClass<{}>) => ImplClass,
     ) {}
 }
 
 export namespace Trait {
+    export type OwnSupertraits<T> = (
+        T extends Trait<infer Supertraits, any, any>
+            ? Supertraits
+            : never
+    )
+    export interface OwnSupertraitsFn extends Fn {
+        return: Trait.OwnSupertraits<this["arg0"]>
+    }
+
     export type OwnAbstract<T> = (
         T extends Trait<any, infer Abstract, any>
             ? Abstract
@@ -88,8 +97,8 @@ export namespace Trait {
     }
 
     export type Supertraits<T> = (
-        T extends Trait<infer Super, any, any>
+        T extends Trait<infer Supertraits, any, any>
-            ? TraitExpression.AllTraits<Super>
+            ? TraitExpression.AllTraits<Supertraits>
             : never
     )
     export interface SupertraitsFn extends Fn {

src/TraitExpressionBuilder.ts

@@ -73,40 +73,36 @@ type SpreadSupertraits<Traits extends Trait<any, any, any>[]> = (
     >
 )
 interface PrependTraitSupertraitsFn extends Fn {
-    return: this["arg0"] extends Trait<infer Super, any, any>
+    return: [...Trait.Supertraits<this["arg0"]>, this["arg0"]]
-        ? Super extends TraitExpression<any, any, infer AllTraits>
-            ? [...AllTraits, this["arg0"]]
-            : never
-        : never
 }
 
 
 type AbstractMembersExtendable<
-    Super  extends AbstractClass<{}>,
+    Superclass extends AbstractClass<{}>,
     Traits     extends Trait<any, any, any>[],
 > = (
     Call<ExtendableFn, [
-        InstanceType<Super>,
+        InstanceType<Superclass>,
         ...Call<Tuples.Map<Trait.OwnAbstractFn>, Traits>,
     ]>
 )
 
 type ImplInstanceExtendable<
-    Super  extends AbstractClass<{}>,
+    Superclass extends AbstractClass<{}>,
     Traits     extends Trait<any, any, any>[],
 > = (
     Call<ExtendableFn, [
-        InstanceType<Super>,
+        InstanceType<Superclass>,
         ...Call<Tuples.Map<Trait.OwnImplInstanceFn>, Traits>,
     ]>
 )
 
 type ImplStaticMembersExtendable<
-    Super  extends AbstractClass<{}>,
+    Superclass extends AbstractClass<{}>,
     Traits     extends Trait<any, any, any>[],
 > = (
     Pipe<[
-        Super,
+        Superclass,
         ...Call<Tuples.Map<Trait.OwnImplClassFn>, Traits>,
     ], [
         Tuples.Map<StaticMembersFn>,
@@ -115,19 +111,19 @@ type ImplStaticMembersExtendable<
 )
 
 type GetTraitExpression<
-    Super     extends AbstractClass<{}>,
+    Superclass extends AbstractClass<{}>,
     OwnTraits  extends Trait<any, any, any>[],
     AllTraits  extends Trait<any, any, any>[],
 > = (
     Call<Tuples.IsEmpty, AllTraits> extends true
         ? "Cannot express an empty list of traits."
-        : AbstractMembersExtendable<Super, AllTraits> extends false
+        : AbstractMembersExtendable<Superclass, AllTraits> extends false
             ? "Type conflict between the traits abstract members and/or the superclass instance."
-            : ImplInstanceExtendable<Super, AllTraits> extends false
+            : ImplInstanceExtendable<Superclass, AllTraits> extends false
                 ? "Type conflict between the traits implementation instances and/or the superclass instance."
-                : ImplStaticMembersExtendable<Super, AllTraits> extends false
+                : ImplStaticMembersExtendable<Superclass, AllTraits> extends false
                     ? "Type conflict between the traits implementation static members and/or the superclass static members."
-                    : TraitExpression<Super, OwnTraits, AllTraits>
+                    : TraitExpression<Superclass, OwnTraits, AllTraits>
 )
 
 

src/tests.ts

@@ -57,7 +57,7 @@ const builder = expression
         StatefulSubscription,
     )
 
-type T = TraitExpression.OwnTraits<typeof builder.expression>
+type T = TraitExpression.AllTraits<typeof builder.expression>
 
 const exp = builder.get()
 type Abs = Implements<typeof exp>