Add a test case

Author: slavapestov

test/decl/protocol/req/associated_type_inference_distributed.swift

@@ -0,0 +1,22 @@
+// RUN: %target-typecheck-verify-swift -enable-experimental-associated-type-inference
+// RUN: not %target-typecheck-verify-swift -disable-experimental-associated-type-inference
+
+// Reduced from the distributed actors implementation. This didn't type check in 5.10
+// but works now.
+
+protocol DistributedActorSystem<SerializationRequirement> {
+  associatedtype SerializationRequirement
+}
+
+protocol DistributedActor where SerializationRequirement == ActorSystem.SerializationRequirement {
+  associatedtype ActorSystem: DistributedActorSystem
+  associatedtype SerializationRequirement
+}
+
+class Worker<ActorSystem>: DistributedActor where ActorSystem: DistributedActorSystem, ActorSystem.SerializationRequirement == Int {}
+
+struct FakeActorSystem: DistributedActorSystem {
+  typealias SerializationRequirement = Int
+}
+
+print(Worker<FakeActorSystem>.SerializationRequirement.self)