Ensure that we map the capture isolation into context

Failing to map the type of an isolation capture into context
caused assertions in type lowering. Fixes the build of the
swift-distributed-actors package.

Author: DougGregor

lib/SILGen/SILGenConcurrency.cpp

@@ -463,8 +463,8 @@ static ManagedValue emitLoadOfCaptureIsolation(SILGenFunction &SGF,
   auto &TC = SGF.SGM.Types;
   auto captureInfo = TC.getLoweredLocalCaptures(constant);
 
-  auto isolatedVarType =
-    isolatedCapture->getInterfaceType()->getCanonicalType();
+  auto isolatedVarType = SGF.F.mapTypeIntoContext(
+    isolatedCapture->getInterfaceType())->getCanonicalType();
 
   // Capture arguments are 1-1 with the lowered capture info.
   auto captures = captureInfo.getCaptures();

test/Distributed/distributed_actor_to_actor.swift

@@ -9,6 +9,7 @@
 // rdar://123970272
 // UNSUPPORTED: CPU=arm64e
 
+import Swift
 import _Concurrency
 import Distributed
 
@@ -39,6 +40,25 @@ func getAnyActor(distributedActor: isolated some DistributedActor) -> any Actor
 // CHECK-IR-NEXT: store ptr %"some DistributedActor.DistributedActor", ptr [[SELF_DA_REQ]]
 // CHECK-IR-NEXT: call ptr @swift_getWitnessTable(ptr @"$sxScA11DistributedMc", ptr %"some DistributedActor", ptr [[CONDITIONAL_REQ_GEP]])
 
+distributed actor WorkerPool<Worker, ActorSystem: DistributedActorSystem>: AsyncSequence, AsyncIteratorProtocol {
+  var level: Int
+  public init(actorSystem system: ActorSystem) async throws {
+    self.actorSystem = system
+    self.level = 0
+
+    // CHECK-SIL: sil private @$s021distributed_actor_to_B010WorkerPoolC0B6SystemACyxq_Gq__tYaKcfcyyYaYbcfU_ : $@convention(thin) @Sendable @async <Worker, ActorSystem where ActorSystem : DistributedActorSystem> (@guaranteed Optional<any Actor>, @sil_isolated @guaranteed WorkerPool<Worker, ActorSystem>) -> @out
+    // CHECK-SIL: hop_to_executor {{%.*}} : $WorkerPool<Worker, ActorSystem>
+    _ = Task {
+      for await x in self {
+        print(x)
+      }
+    }
+  }
+
+  nonisolated func makeAsyncIterator() -> WorkerPool { self }
+  nonisolated func next() async -> Int? { nil }
+}
+
 // CHECK-SIL-LABEL: sil_witness_table shared <Self where Self : DistributedActor> T: Actor module Distributed {
 // CHECK-SIL-NEXT: method #Actor.unownedExecutor!getter: <Self where Self : Actor> (Self) -> () -> UnownedSerialExecutor : @$sxScA11DistributedScA15unownedExecutorScevgTW
 // CHECK-SIL-NEXT: conditional_conformance (Self: DistributedActor): dependent