Fixed SpreadSupertraits

src/TraitExpressionBuilder.ts

@@ -1,4 +1,3 @@
-import { Call, Fn, Tuples } from "hotscript"
 import { uniq } from "lodash-es"
 import { AbstractClass } from "type-fest"
 import { Trait, TraitTuple } from "./Trait"
@@ -6,15 +5,15 @@ import { TraitExpression } from "./TraitExpression"
 import { Extendable, StaticMembers } from "./util"
 
 
-type SpreadSupertraits<Traits extends Trait<any, any, any, any>[]> = (
-    Call<
-        Tuples.FlatMap<PrependTraitSupertraitsFn>,
-        Traits
-    >
+type SpreadSupertraits<T> = (
+    T extends [infer Trait, ...infer Rest]
+        ? [
+            ...Trait.Supertraits<Trait>,
+            Trait,
+            ...SpreadSupertraits<Rest>,
+        ]
+        : []
 )
-interface PrependTraitSupertraitsFn extends Fn {
-    return: [...Trait.Supertraits<this["arg0"]>, this["arg0"]]
-}
 
 
 type InstanceExtendable<
@@ -81,10 +80,7 @@ class TraitExpressionBuilder<
         >[]
     >(
         ...traits: T
-    ): TraitExpressionBuilder<
-        Superclass,
-        [...Traits, ...SpreadSupertraits<T>]
-    > {
+    ) {
         return new TraitExpressionBuilder(
             this.expressionSuperclass,