Merge pull request swiftlang#83899 from slavapestov/fix-issue83539

IRGen: Fix crash trying to emit capture descriptor involving element archetype

Author: slavapestov

lib/IRGen/GenHeap.cpp

@@ -1576,24 +1576,6 @@ class FixedBoxTypeInfoBase : public BoxTypeInfo {
       boxedInterfaceType = boxedType.mapTypeOutOfContext();
     }
 
-    {
-      // FIXME: This seems wrong. We used to just mangle opened archetypes as
-      // their interface type. Let's make that explicit now.
-      auto astType = boxedInterfaceType.getASTType();
-      astType =
-          astType
-              .transformRec([](Type t) -> std::optional<Type> {
-                if (auto *openedExistential = t->getAs<ExistentialArchetypeType>()) {
-                  auto &ctx = openedExistential->getASTContext();
-                  return ctx.TheSelfType;
-                }
-                return std::nullopt;
-              })
-              ->getCanonicalType();
-      boxedInterfaceType = SILType::getPrimitiveType(
-          astType, boxedInterfaceType.getCategory());
-    }
-    
     auto boxDescriptor = IGF.IGM.getAddrOfBoxDescriptor(
         boxedInterfaceType,
         env ? env->getGenericSignature().getCanonicalSignature()

lib/IRGen/GenReflection.cpp

@@ -1693,6 +1693,9 @@ llvm::Constant *IRGenModule::getAddrOfFieldName(StringRef Name) {
 llvm::Constant *
 IRGenModule::getAddrOfBoxDescriptor(SILType BoxedType,
                                     CanGenericSignature genericSig) {
+  if (BoxedType.hasLocalArchetype())
+    return llvm::Constant::getNullValue(CaptureDescriptorPtrTy);
+
   if (IRGen.Opts.ReflectionMetadata != ReflectionMetadataMode::Runtime)
     return llvm::Constant::getNullValue(CaptureDescriptorPtrTy);
 

test/Reflection/box_descriptor_with_element_archetype.swift

@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -emit-ir %s -target %target-swift-5.9-abi-triple
+
+public protocol P {}
+
+public struct G<T>: P {
+  let s1: String
+  let s2: String
+}
+
+public func f<each T>(t: repeat G<each T>) {
+    var ts: [any P] = []
+    for x in repeat each t {
+        ts.append(x)
+    }
+}