Merge pull request swiftlang#83019 from DougGregor/prohibit-isolated-conformance-capture-check

Use the "prohibits isolated conformances" check for capture metatypes

Author: DougGregor

lib/Sema/TypeCheckConcurrency.cpp

@@ -3103,36 +3103,22 @@ namespace {
           mayExecuteConcurrentlyWith(
               localFunc.getAsDeclContext(), getDeclContext(),
               /*includeSending*/true)) {
-        auto innermostGenericDC = localFunc.getAsDeclContext();
-        while (innermostGenericDC && !innermostGenericDC->isGenericContext())
-          innermostGenericDC = innermostGenericDC->getParent();
-
-        GenericSignature genericSig = innermostGenericDC
-            ? innermostGenericDC->getGenericSignatureOfContext()
-            : GenericSignature();
-
         for (const auto &capturedType :
                  localFunc.getCaptureInfo().getCapturedTypes()) {
-          unsigned genericDepth;
           Type type = capturedType.getType();
           if (auto archetype = type->getAs<ArchetypeType>()) {
-            genericDepth = archetype->getInterfaceType()->getRootGenericParam()
-                ->getDepth();
-          } else if (type->isTypeParameter()) {
-            genericDepth = type->getRootGenericParam()->getDepth();
+            // If the generic signature of the environment prohibits this
+            // type to have an isolated conformance, there is nothing to
+            // diagnose.
+            Type interfaceType = archetype->getInterfaceType();
+            auto genericEnv = archetype->getGenericEnvironment();
+            auto genericSig = genericEnv->getGenericSignature();
+            if (genericSig->prohibitsIsolatedConformance(interfaceType))
+              continue;
           } else {
             continue;
           }
 
-          // If the local function is generic and this is one of its generic
-          // parameters, ignore it.
-          if (genericSig.getNextDepth() > 0 &&
-              genericDepth >= genericSig.getNextDepth())
-            continue;
-
-          if (type->isTypeParameter() && innermostGenericDC)
-            type = innermostGenericDC->mapTypeIntoContext(type);
-
           // Check that the metatype is sendable.
           SendableCheckContext sendableContext(getDeclContext(), preconcurrency);
           diagnoseNonSendableTypes(MetatypeType::get(type),

test/Concurrency/sendable_metatype_typecheck.swift

@@ -21,7 +21,7 @@ func testSendableExistential() {
 nonisolated func acceptMeta<T>(_: T.Type) { }
 
 nonisolated func staticCallThroughMetaVal<T: Q>(_: T.Type) {
-  let x = T.self // expected-warning{{capture of non-Sendable type 'T.Type' in an isolated closure}}
+  let x = T.self
   Task.detached {
     x.g() // expected-warning{{capture of non-Sendable type 'T.Type' in an isolated closure}}
   }
@@ -35,7 +35,7 @@ nonisolated func captureThroughMetaValMoReqs<T>(_: T.Type) {
 }
 
 nonisolated func passMetaVal<T: Q>(_: T.Type) {
-  let x = T.self // expected-warning{{capture of non-Sendable type 'T.Type' in an isolated closure}}
+  let x = T.self
   Task.detached {
     acceptMeta(x) // expected-warning{{capture of non-Sendable type}}
   }
@@ -188,3 +188,20 @@ func f<T: P>(_: T.Type) {
     }
   }
 }
+
+func sendableSequence<S: AsyncSequence & Sendable>(_ s: S) throws {
+  Task.detached {
+    for try await i in s {
+      print(i)
+    }
+  }
+}
+
+func nonSendableSequence<S: AsyncSequence>(_ s: S) throws {
+  Task.detached {
+    for try await i in s { // expected-warning{{capture of non-Sendable type 'S.AsyncIterator.Type' in an isolated closure}}
+      // expected-warning@-1{{capture of non-Sendable type 'S.Type' in an isolated closure}}
+      print(i)
+    }
+  }
+}