[Distributed] Handle DA declared inside a generic type (#71492)

Author: ktoso

lib/Sema/CodeSynthesisDistributedActor.cpp

@@ -346,18 +346,16 @@ deriveBodyDistributed_thunk(AbstractFunctionDecl *thunk, void *context) {
 
   // --- Recording invocation details
   // -- recordGenericSubstitution(s)
-  if (thunk->isGeneric() || nominal->isGeneric()) {
+  if (auto genEnv = thunk->getGenericEnvironment()) {
     auto recordGenericSubstitutionDecl =
         C.getRecordGenericSubstitutionOnDistributedInvocationEncoder(invocationEncoderDecl);
     assert(recordGenericSubstitutionDecl);
     auto recordGenericSubstitutionDeclRef =
         UnresolvedDeclRefExpr::createImplicit(
             C, recordGenericSubstitutionDecl->getName());
 
-    auto signature = thunk->getGenericSignature();
-    for (auto genParamType : signature.getGenericParams()) {
-
-      auto tyExpr = TypeExpr::createImplicit(thunk->mapTypeIntoContext(genParamType), C);
+    for (auto genParamType : genEnv->getGenericParams()) {
+      auto tyExpr = TypeExpr::createImplicit(genEnv->mapTypeIntoContext(genParamType), C);
       auto subTypeExpr = new (C) DotSelfExpr(
           tyExpr,
           sloc, sloc, tyExpr->getType());

test/Distributed/Runtime/distributed_actor_func_calls_remoteCall_da_in_generic_type.swift

@@ -0,0 +1,69 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -disable-availability-checking %S/../Inputs/FakeDistributedActorSystems.swift
+// RUN: %target-build-swift -module-name main  -Xfrontend -disable-availability-checking -j2 -parse-as-library -I %t %s %S/../Inputs/FakeDistributedActorSystems.swift -o %t/a.out
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s --color
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: distributed
+
+// rdar://76038845
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+// UNSUPPORTED: OS=windows-msvc
+
+import Distributed
+import FakeDistributedActorSystems
+
+typealias DefaultDistributedActorSystem = FakeRoundtripActorSystem
+
+struct Outer: Sendable, Codable {
+  distributed actor Greeter<Element> where Element: Sendable & Codable {
+    distributed func hello() -> String {
+      return "Hello, \(Element.self)!"
+    }
+  }
+}
+
+struct OuterGeneric<Element>: Sendable, Codable where Element: Sendable & Codable {
+  distributed actor Greeter {
+    distributed func hello() -> String {
+      return "Hello, \(Element.self)!"
+    }
+  }
+}
+
+func test() async throws {
+  let system = DefaultDistributedActorSystem()
+
+  do {
+    let local = Outer.Greeter<String>(actorSystem: system)
+    let ref = try Outer.Greeter<String>.resolve(id: local.id, using: system)
+    let response = try await ref.hello()
+    // CHECK: > encode generic sub: Swift.String
+    // CHECK: >> remoteCall: on:main.Outer.Greeter<Swift.String>, target:Greeter.hello(), invocation:FakeInvocationEncoder(genericSubs: [Swift.String], arguments: [], returnType: Optional(Swift.String), errorType: nil), throwing:Swift.Never, returning:Swift.String
+    print("response 1: \(response)")
+    // CHECK: response 1: Hello, String!
+  }
+
+  do {
+    let local = OuterGeneric<String>.Greeter(actorSystem: system)
+    let ref = try OuterGeneric<String>.Greeter.resolve(id: local.id, using: system)
+    let response = try await ref.hello()
+    // CHECK: > encode generic sub: Swift.String
+    // CHECK: >> remoteCall: on:main.OuterGeneric<Swift.String>.Greeter, target:Greeter.hello(), invocation:FakeInvocationEncoder(genericSubs: [Swift.String], arguments: [], returnType: Optional(Swift.String), errorType: nil), throwing:Swift.Never, returning:Swift.String
+    print("response 2: \(response)")
+    // CHECK: response 2: Hello, String!
+  }
+
+
+
+}
+
+@main struct Main {
+  static func main() async {
+    try! await test()
+  }
+}