[Distributed] Map into context computed property result type for SerReq checking (#75467)

Author: ktoso

lib/Sema/TypeCheckDistributed.cpp

@@ -420,7 +420,10 @@ static bool checkDistributedTargetResultType(
   if (auto func = dyn_cast<FuncDecl>(valueDecl)) {
     resultType = func->mapTypeIntoContext(func->getResultInterfaceType());
   } else if (auto var = dyn_cast<VarDecl>(valueDecl)) {
-    resultType = var->getInterfaceType();
+    // Distributed computed properties are always getters,
+    // so get the get accessor for mapping the type into context:
+    auto getter = var->getAccessor(swift::AccessorKind::Get);
+    resultType = getter->mapTypeIntoContext(var->getInterfaceType());
   } else {
     llvm_unreachable("Unsupported distributed target");
   }

test/Distributed/distributed_protocols_distributed_func_serialization_requirements.swift

@@ -96,6 +96,18 @@ extension ProtocolWithChecksSeqReqDA {
   }
 }
 
+protocol Recipient: DistributedActor where ActorSystem == FakeActorSystem {
+  associatedtype Info: Sendable & Codable // is Codable, should be ok
+  distributed var info: Info { get async }
+  distributed func getInfo() -> Info
+}
+
+distributed actor RecipientImpl: Recipient {
+  typealias Info = String
+  distributed var info: Info { "info" }
+  distributed func getInfo() -> Info { "info" }
+}
+
 // FIXME(distributed): remove the -verify-ignore-unknown
 // <unknown>:0: error: unexpected error produced: instance method 'recordReturnType' requires that 'NotCodable' conform to 'Decodable'
 // <unknown>:0: error: unexpected error produced: instance method 'recordReturnType' requires that 'NotCodable' conform to 'Encodable'