diff --git a/packages/hydrooj/src/model/contest.ts b/packages/hydrooj/src/model/contest.ts
index 122a04f98..a8fe73f6b 100644
--- a/packages/hydrooj/src/model/contest.ts
+++ b/packages/hydrooj/src/model/contest.ts
@@ -70,9 +70,9 @@ export function isExtended(tdoc: Tdoc) {
     return tdoc.penaltySince.getTime() <= now && now < tdoc.endAt.getTime();
 }
 
-function buildContestRule<T>(def: Optional<ContestRule<T>, 'applyProjection'>): ContestRule<T>;
-function buildContestRule<T>(def: Partial<ContestRule<T>>, baseRule: ContestRule<T>): ContestRule<T>;
-function buildContestRule<T>(def: Partial<ContestRule<T>>, baseRule: ContestRule<T> = {} as any) {
+export function buildContestRule<T>(def: Optional<ContestRule<T>, 'applyProjection'>): ContestRule<T>;
+export function buildContestRule<T>(def: Partial<ContestRule<T>>, baseRule: ContestRule<T>): ContestRule<T>;
+export function buildContestRule<T>(def: Partial<ContestRule<T>>, baseRule: ContestRule<T> = {} as any) {
     const base = baseRule._originalRule || { applyProjection: (_, rdoc) => rdoc };
     const funcs = ['scoreboard', 'scoreboardRow', 'scoreboardHeader', 'stat', 'applyProjection'];
     const f = {};