[SILGen] Concurrency: Fix caller isolated closures to hop to the right actor

Closures that are caller isolated used to still hop to the generic
executor, which is incorrect.

Author: xedin

lib/SILGen/SILGenConcurrency.cpp

@@ -206,10 +206,14 @@ void SILGenFunction::emitExpectedExecutorProlog() {
     switch (actorIsolation.getKind()) {
     case ActorIsolation::Unspecified:
     case ActorIsolation::Nonisolated:
-    case ActorIsolation::CallerIsolationInheriting:
     case ActorIsolation::NonisolatedUnsafe:
       break;
 
+    case ActorIsolation::CallerIsolationInheriting:
+      assert(F.isAsync());
+      setExpectedExecutorForParameterIsolation(*this, actorIsolation);
+      break;
+
     case ActorIsolation::Erased:
       llvm_unreachable("closure cannot have erased isolation");
 

test/Concurrency/attr_execution/conversions_silgen.swift

@@ -428,21 +428,31 @@ func conversionsFromSyncToAsync(_ x: @escaping @Sendable (NonSendableKlass) -> V
 
 func testThatClosuresAssumeIsolation(fn: inout nonisolated(nonsending) (Int) async -> Void) {
   // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaYCcfU_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> ()
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>):
+  // CHECK: hop_to_executor [[EXECUTOR]]
   let _: nonisolated(nonsending) () async -> Void = {
     42
   }
 
   func testParam(_: nonisolated(nonsending) () async throws -> Void) {}
 
   // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaYCXEfU0_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>) -> @error any Error
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>):
+  // CHECK: hop_to_executor [[EXECUTOR]]
   testParam { 42 }
 
   // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFyyYaXEfU1_ : $@convention(thin) @async () -> ()
+  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]]
   testParam { @concurrent in 42 }
 
   // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFySiYaYCcfU2_ : $@convention(thin) @async (@sil_isolated @sil_implicit_leading_param @guaranteed Optional<any Actor>, Int) -> ()
+  // CHECK: bb0([[EXECUTOR:%.*]] : @guaranteed $Optional<any Actor>, %1 : $Int):
+  // CHECK: hop_to_executor [[EXECUTOR]]
   fn = { _ in }
 
   // CHECK-LABEL: sil private [ossa] @$s21attr_execution_silgen31testThatClosuresAssumeIsolation2fnyySiYaYCcz_tFySiYacfU3_ : $@convention(thin) @async (Int) -> ()
+  // CHECK: [[GENERIC_EXECUTOR:%.*]] = enum $Optional<Builtin.Executor>, #Optional.none!enumelt
+  // CHECK: hop_to_executor [[GENERIC_EXECUTOR]]
   fn = { @concurrent _ in }
 }