fix(router): make currentSnapshot required in CanMatchFn

it was only optional to avoid a breaking change in a minor BREAKING CHANGE: The `currentSnapshot` parameter in `CanMatchFn` and the `canMatch` method of the `CanMatch` interface is now required. While this was already the behavior of the Router at runtime, existing class implementations of `CanMatch` must now include the third argument to satisfy the interface.
angular · atscott · Mar 4, 2026 · Mar 20, 2026 · Apr 1, 2026 · Mar 31, 2026
commit e9046e998a012fc0aa648966cfaefaf57df2a3e2
diff --git a/adev/src/content/guide/routing/route-guards.md b/adev/src/content/guide/routing/route-guards.md
@@ -125,11 +125,16 @@ It has access to the following default arguments:
 
 - `route`: `Route` - The route configuration being evaluated
 - `segments`: `UrlSegment[]` - The URL segments that have not been consumed by previous parent route evaluations
+- `currentSnapshot: PartialMatchRouteSnapshot` - The current route snapshot up to this point in the matching process
 
 It can return the [standard return guard types](#route-guard-return-types), but when it returns `false`, Angular tries other matching routes instead of completely blocking navigation.
 
 ```ts
-export const featureToggleGuard: CanMatchFn = (route: Route, segments: UrlSegment[]) => {
+export const featureToggleGuard: CanMatchFn = (
+  route: Route,
+  segments: UrlSegment[],
+  currentSnapshot: PartialMatchRouteSnapshot,
+) => {
   const featureService = inject(FeatureService);
   return featureService.isFeatureEnabled('newDashboard');
 };

diff --git a/goldens/public-api/router/index.api.md b/goldens/public-api/router/index.api.md
@@ -149,11 +149,11 @@ export type CanLoadFn = (route: Route, segments: UrlSegment[]) => MaybeAsync<Gua
 // @public
 export interface CanMatch {
     // (undocumented)
-    canMatch(route: Route, segments: UrlSegment[], currentSnapshot?: PartialMatchRouteSnapshot): MaybeAsync<GuardResult>;
+    canMatch(route: Route, segments: UrlSegment[], currentSnapshot: PartialMatchRouteSnapshot): MaybeAsync<GuardResult>;
 }
 
 // @public
-export type CanMatchFn = (route: Route, segments: UrlSegment[], currentSnapshot?: PartialMatchRouteSnapshot) => MaybeAsync<GuardResult>;
+export type CanMatchFn = (route: Route, segments: UrlSegment[], currentSnapshot: PartialMatchRouteSnapshot) => MaybeAsync<GuardResult>;
 
 // @public
 export class ChildActivationEnd {

diff --git a/packages/examples/router/route_functional_guards.ts b/packages/examples/router/route_functional_guards.ts
@@ -14,6 +14,7 @@ import {
   CanActivateChildFn,
   CanActivateFn,
   CanMatchFn,
+	PartialMatchRouteSnapshot,
   provideRouter,
   ResolveFn,
   Route,
@@ -111,7 +112,11 @@ bootstrapApplication(App, {
 // #enddocregion
 
 // #docregion CanMatchFn
-const canMatchTeam: CanMatchFn = (route: Route, segments: UrlSegment[]) => {
+const canMatchTeam: CanMatchFn = (
+  route: Route,
+  segments: UrlSegment[],
+  currentSnapshot: PartialMatchRouteSnapshot,
+) => {
   return inject(PermissionsService).canMatch(inject(UserToken));
 };
 

diff --git a/packages/router/src/models.ts b/packages/router/src/models.ts
@@ -1113,7 +1113,11 @@ export type CanDeactivateFn<T> = (
  * class CanMatchTeamSection implements CanMatch {
  *   constructor(private permissions: Permissions, private currentUser: UserToken) {}
  *
- *   canMatch(route: Route, segments: UrlSegment[]): Observable<boolean>|Promise<boolean>|boolean {
+ *   canMatch(
+ *     route: Route,
+ *     segments: UrlSegment[],
+ *     currentSnapshot: PartialMatchRouteSnapshot,
+ *   ): Observable<boolean> | Promise<boolean> | boolean {
  *     return this.permissions.canAccess(this.currentUser, route, segments);
  *   }
  * }
@@ -1154,7 +1158,7 @@ export interface CanMatch {
   canMatch(
     route: Route,
     segments: UrlSegment[],
-    currentSnapshot?: PartialMatchRouteSnapshot,
+    currentSnapshot: PartialMatchRouteSnapshot,
   ): MaybeAsync<GuardResult>;
 }
 
@@ -1172,9 +1176,7 @@ export interface CanMatch {
  *
  * @param route The route configuration.
  * @param segments The URL segments that have not been consumed by previous parent route evaluations.
- * @param currentSnapshot The current route snapshot up to this point in the matching process. While this parameter is optional,
- * it will always be defined when called by the Router. It is only optional for backwards compatibility with functions defined prior
- * to the introduction of this parameter.
+ * @param currentSnapshot The current route snapshot up to this point in the matching process.
  *
  * @publicApi
  * @see {@link Route}
@@ -1183,7 +1185,7 @@ export interface CanMatch {
 export type CanMatchFn = (
   route: Route,
   segments: UrlSegment[],
-  currentSnapshot?: PartialMatchRouteSnapshot,
+  currentSnapshot: PartialMatchRouteSnapshot,
 ) => MaybeAsync<GuardResult>;
 
 /**