diff --git a/include/swift/AST/NameLookupRequests.h b/include/swift/AST/NameLookupRequests.h
index 0ce342507dfc7..e5cb28ab9e382 100644
--- a/include/swift/AST/NameLookupRequests.h
+++ b/include/swift/AST/NameLookupRequests.h
@@ -348,11 +348,44 @@ class TypeDeclsFromWhereClauseRequest :
                                        ExtensionDecl *ext) const;
 };
 
+/// The owning decl for a given custom attribute, or a DeclContext for a
+/// custom attribute in e.g a closure or inheritance clause.
+class CustomAttrOwner final {
+  llvm::PointerUnion<const Decl *, DeclContext *> Owner;
+
+public:
+  CustomAttrOwner() : Owner(nullptr) {}
+  CustomAttrOwner(const Decl *D) : Owner(D) {}
+  CustomAttrOwner(DeclContext *DC) : Owner(DC) {}
+
+  const Decl *getAsDecl() const {
+    return Owner.dyn_cast<const Decl *>();
+  }
+
+  DeclContext *getDeclContext() const;
+
+  friend bool operator==(const CustomAttrOwner &lhs,
+                         const CustomAttrOwner &rhs) {
+    return lhs.Owner == rhs.Owner;
+  }
+
+  friend bool operator!=(const CustomAttrOwner &lhs,
+                         const CustomAttrOwner &rhs) {
+    return !(lhs == rhs);
+  }
+
+  friend hash_code hash_value(const CustomAttrOwner &owner) {
+    return llvm::hash_value(owner.Owner);
+  }
+};
+
+void simple_display(llvm::raw_ostream &out, const CustomAttrOwner &owner);
+
 /// Request the nominal type declaration to which the given custom
 /// attribute refers.
 class CustomAttrNominalRequest :
     public SimpleRequest<CustomAttrNominalRequest,
-                         NominalTypeDecl *(CustomAttr *, DeclContext *),
+                         NominalTypeDecl *(CustomAttr *, CustomAttrOwner),
                          RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -362,7 +395,7 @@ class CustomAttrNominalRequest :
 
   // Evaluation.
   NominalTypeDecl *
-  evaluate(Evaluator &evaluator, CustomAttr *attr, DeclContext *dc) const;
+  evaluate(Evaluator &evaluator, CustomAttr *attr, CustomAttrOwner owner) const;
 
 public:
   // Caching
diff --git a/include/swift/Basic/Features.def b/include/swift/Basic/Features.def
index cc2665001e14c..8e1ef2362533e 100644
--- a/include/swift/Basic/Features.def
+++ b/include/swift/Basic/Features.def
@@ -544,6 +544,10 @@ EXPERIMENTAL_FEATURE(DefaultIsolationPerFile, false)
 /// Enable @_lifetime attribute
 SUPPRESSIBLE_EXPERIMENTAL_FEATURE(Lifetimes, true)
 
+/// Excludes 'private' properties with initial values from the memberwise
+/// initializer.
+EXPERIMENTAL_FEATURE(ExcludePrivateFromMemberwiseInit, false)
+
 /// Allow macro based aliases to be imported into Swift
 EXPERIMENTAL_FEATURE(ImportMacroAliases, true)
 
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 5cbfe78d72d38..17d75324cf6a5 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -574,7 +574,7 @@ Type Decl::getResolvedCustomAttrType(CustomAttr *attr) const {
 
   auto dc = getDeclContext();
   auto *nominal = evaluateOrDefault(
-      getASTContext().evaluator, CustomAttrNominalRequest{attr, dc}, nullptr);
+      getASTContext().evaluator, CustomAttrNominalRequest{attr, this}, nullptr);
   if (!nominal)
     return Type();
 
@@ -8431,10 +8431,22 @@ bool VarDecl::isMemberwiseInitialized(bool preferDeclaredProperties) const {
   // If this is a stored property, and not a backing property in a case where
   // we only want to see the declared properties, it can be memberwise
   // initialized.
-  if (hasStorage() && preferDeclaredProperties &&
-      isBackingStorageForDeclaredProperty(this))
-    return false;
-
+  if (hasStorage()) {
+    if (isBackingStorageForDeclaredProperty(this)) {
+      if (preferDeclaredProperties)
+        return false;
+    } else if (getASTContext().LangOpts.hasFeature(Feature::ExcludePrivateFromMemberwiseInit)) {
+      // Private variables with initial values are never memberwise initialized.
+      if (getFormalAccess() == AccessLevel::Private) {
+        if (hasInitialValue())
+          return false;
+        if (auto *PBD = getParentPatternBinding()) {
+          if (PBD->isDefaultInitializable())
+            return false;
+        }
+      }
+    }
+  }
   // If this is a computed property with `init` accessor, it's
   // memberwise initializable when it could be used to initialize
   // other stored properties.
@@ -8696,10 +8708,9 @@ VarDecl::getAttachedPropertyWrapperTypeInfo(unsigned i) const {
       return PropertyWrapperTypeInfo();
 
     auto attr = attrs[i];
-    auto dc = getDeclContext();
     ASTContext &ctx = getASTContext();
     nominal = evaluateOrDefault(
-        ctx.evaluator, CustomAttrNominalRequest{attr, dc}, nullptr);
+        ctx.evaluator, CustomAttrNominalRequest{attr, this}, nullptr);
   }
 
   if (!nominal)
diff --git a/lib/AST/FeatureSet.cpp b/lib/AST/FeatureSet.cpp
index 0184fe7e940b2..68ec218e33ef0 100644
--- a/lib/AST/FeatureSet.cpp
+++ b/lib/AST/FeatureSet.cpp
@@ -127,6 +127,7 @@ UNINTERESTING_FEATURE(NonisolatedNonsendingByDefault)
 UNINTERESTING_FEATURE(KeyPathWithMethodMembers)
 UNINTERESTING_FEATURE(ImportMacroAliases)
 UNINTERESTING_FEATURE(NoExplicitNonIsolated)
+UNINTERESTING_FEATURE(ExcludePrivateFromMemberwiseInit)
 
 // TODO: Return true for inlinable function bodies with module selectors in them
 UNINTERESTING_FEATURE(ModuleSelector)
diff --git a/lib/AST/NameLookup.cpp b/lib/AST/NameLookup.cpp
index 4f785711cf9f1..5c4ed948f495e 100644
--- a/lib/AST/NameLookup.cpp
+++ b/lib/AST/NameLookup.cpp
@@ -3961,9 +3961,24 @@ GenericParamListRequest::evaluate(Evaluator &evaluator, GenericContext *value) c
       parsedGenericParams->getRAngleLoc());
 }
 
+static bool shouldPreferPropertyWrapperOverMacro(CustomAttrOwner owner) {
+  // If we have a VarDecl in a local context, prefer to look for a property
+  // wrapper if one exists. This is necessary since we don' properly support
+  // peer declarations in local contexts, so want to use a property wrapper if
+  // one exists.
+  if (auto *D = dyn_cast_or_null<VarDecl>(owner.getAsDecl())) {
+    if (!isa<ParamDecl>(D) && D->getDeclContext()->isLocalContext())
+      return true;
+  }
+  return false;
+}
+
 NominalTypeDecl *
 CustomAttrNominalRequest::evaluate(Evaluator &evaluator,
-                                   CustomAttr *attr, DeclContext *dc) const {
+                                   CustomAttr *attr,
+                                   CustomAttrOwner owner) const {
+  auto *dc = owner.getDeclContext();
+
   // Look for names at module scope, so we don't trigger name lookup for
   // nested scopes. At this point, we're looking to see whether there are
   // any suitable macros.
@@ -3972,7 +3987,8 @@ CustomAttrNominalRequest::evaluate(Evaluator &evaluator,
   auto macroName = (macro) ? macro->getNameRef() : DeclNameRef();
   auto macros = namelookup::lookupMacros(dc, moduleName, macroName,
                                          getAttachedMacroRoles());
-  if (!macros.empty())
+  auto shouldPreferPropWrapper = shouldPreferPropertyWrapperOverMacro(owner);
+  if (!macros.empty() && !shouldPreferPropWrapper)
     return nullptr;
 
   // Find the types referenced by the custom attribute.
@@ -3992,6 +4008,15 @@ CustomAttrNominalRequest::evaluate(Evaluator &evaluator,
   auto nominals = resolveTypeDeclsToNominal(evaluator, ctx, decls.first,
                                             ResolveToNominalOptions(),
                                             modulesFound, anyObject);
+  if (shouldPreferPropWrapper) {
+    auto hasPropWrapper = llvm::any_of(nominals, [](NominalTypeDecl *NTD) {
+      return NTD->getAttrs().hasAttribute<PropertyWrapperAttr>();
+    });
+    if (!macros.empty() && !hasPropWrapper)
+      return nullptr;
+
+    ASSERT(macros.empty() && "now preferring property wrapper");
+  }
   if (nominals.size() == 1 && !isa<ProtocolDecl>(nominals.front()))
     return nominals.front();
 
diff --git a/lib/AST/NameLookupRequests.cpp b/lib/AST/NameLookupRequests.cpp
index 956deb29ae982..407fc90d976b0 100644
--- a/lib/AST/NameLookupRequests.cpp
+++ b/lib/AST/NameLookupRequests.cpp
@@ -230,6 +230,26 @@ void ExtendedNominalRequest::writeDependencySink(
   tracker.addPotentialMember(value);
 }
 
+//----------------------------------------------------------------------------//
+// CustomAttrOwner
+//----------------------------------------------------------------------------//
+
+DeclContext *CustomAttrOwner::getDeclContext() const {
+  if (auto *D = getAsDecl())
+    return D->getDeclContext();
+
+  return Owner.dyn_cast<DeclContext *>();
+}
+
+void swift::simple_display(llvm::raw_ostream &out,
+                           const CustomAttrOwner &owner) {
+  if (auto *D = owner.getAsDecl()) {
+    simple_display(out, D);
+  } else {
+    simple_display(out, owner.getDeclContext());
+  }
+}
+
 //----------------------------------------------------------------------------//
 // Destructor computation.
 //----------------------------------------------------------------------------//
diff --git a/lib/Basic/LangOptions.cpp b/lib/Basic/LangOptions.cpp
index 114b81a20ae53..4d4f0bd345c7e 100644
--- a/lib/Basic/LangOptions.cpp
+++ b/lib/Basic/LangOptions.cpp
@@ -42,6 +42,8 @@ LangOptions::LangOptions() {
 #define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description)
 #include "swift/Basic/Features.def"
 
+  enableFeature(Feature::ExcludePrivateFromMemberwiseInit);
+
   // Special case: remove macro support if the compiler wasn't built with a
   // host Swift.
 #if !SWIFT_BUILD_SWIFT_SYNTAX
diff --git a/lib/Sema/TypeCheckAttr.cpp b/lib/Sema/TypeCheckAttr.cpp
index 4190a9ce40b1f..fc4a3dc010fd2 100644
--- a/lib/Sema/TypeCheckAttr.cpp
+++ b/lib/Sema/TypeCheckAttr.cpp
@@ -4588,7 +4588,7 @@ void AttributeChecker::visitCustomAttr(CustomAttr *attr) {
 
   // Figure out which nominal declaration this custom attribute refers to.
   auto *nominal = evaluateOrDefault(
-    Ctx.evaluator, CustomAttrNominalRequest{attr, dc}, nullptr);
+    Ctx.evaluator, CustomAttrNominalRequest{attr, D}, nullptr);
 
   if (!nominal) {
     if (attr->isInvalid())
@@ -8742,8 +8742,7 @@ static void forEachCustomAttribute(
     auto *mutableAttr = const_cast<CustomAttr *>(attr);
 
     auto *nominal = evaluateOrDefault(
-        ctx.evaluator,
-        CustomAttrNominalRequest{mutableAttr, decl->getDeclContext()}, nullptr);
+        ctx.evaluator, CustomAttrNominalRequest{mutableAttr, decl}, nullptr);
     if (!nominal)
       continue;
 
diff --git a/lib/Sema/TypeCheckConcurrency.cpp b/lib/Sema/TypeCheckConcurrency.cpp
index e813d4edf700d..eeb953e044df6 100644
--- a/lib/Sema/TypeCheckConcurrency.cpp
+++ b/lib/Sema/TypeCheckConcurrency.cpp
@@ -311,16 +311,16 @@ VarDecl *GlobalActorInstanceRequest::evaluate(
 }
 
 std::optional<std::pair<CustomAttr *, NominalTypeDecl *>>
-swift::checkGlobalActorAttributes(SourceLoc loc, DeclContext *dc,
+swift::checkGlobalActorAttributes(SourceLoc loc, CustomAttrOwner owner,
                                   ArrayRef<CustomAttr *> attrs) {
-  ASTContext &ctx = dc->getASTContext();
+  ASTContext &ctx = owner.getDeclContext()->getASTContext();
 
   CustomAttr *globalActorAttr = nullptr;
   NominalTypeDecl *globalActorNominal = nullptr;
   for (auto attr : attrs) {
     // Figure out which nominal declaration this custom attribute refers to.
     auto *nominal = evaluateOrDefault(ctx.evaluator,
-                                      CustomAttrNominalRequest{attr, dc},
+                                      CustomAttrNominalRequest{attr, owner},
                                       nullptr);
 
     if (!nominal)
@@ -352,11 +352,11 @@ std::optional<std::pair<CustomAttr *, NominalTypeDecl *>>
 GlobalActorAttributeRequest::evaluate(
     Evaluator &evaluator,
     llvm::PointerUnion<Decl *, ClosureExpr *> subject) const {
-  DeclContext *dc = nullptr;
+  CustomAttrOwner owner;
   DeclAttributes *declAttrs = nullptr;
   SourceLoc loc;
   if (auto decl = subject.dyn_cast<Decl *>()) {
-    dc = decl->getDeclContext();
+    owner = decl;
     declAttrs = &decl->getAttrs();
     // HACK: `getLoc`, when querying the attr from a serialized decl,
     // depending on deserialization order, may launch into arbitrary
@@ -372,7 +372,7 @@ GlobalActorAttributeRequest::evaluate(
     loc = decl->getLoc(/* SerializedOK */ false);
   } else {
     auto closure = cast<ClosureExpr *>(subject);
-    dc = closure;
+    owner = closure;
     declAttrs = &closure->getAttrs();
     loc = closure->getLoc();
   }
@@ -385,7 +385,7 @@ GlobalActorAttributeRequest::evaluate(
   }
 
   // Look for a global actor attribute.
-  auto result = checkGlobalActorAttributes(loc, dc, attrs);
+  auto result = checkGlobalActorAttributes(loc, owner, attrs);
   if (!result)
     return std::nullopt;
 
diff --git a/lib/Sema/TypeCheckConcurrency.h b/lib/Sema/TypeCheckConcurrency.h
index 50b01165ba306..7deb56d25fa17 100644
--- a/lib/Sema/TypeCheckConcurrency.h
+++ b/lib/Sema/TypeCheckConcurrency.h
@@ -32,6 +32,7 @@ namespace swift {
 
 class AbstractFunctionDecl;
 class ConstructorDecl;
+class CustomAttrOwner;
 class ActorIsolation;
 class AnyFunctionType;
 class ASTContext;
@@ -609,7 +610,7 @@ bool diagnoseSendabilityErrorBasedOn(
 /// and perform any necessary resolution and diagnostics, returning the
 /// global actor attribute and type it refers to (or \c std::nullopt).
 std::optional<std::pair<CustomAttr *, NominalTypeDecl *>>
-checkGlobalActorAttributes(SourceLoc loc, DeclContext *dc,
+checkGlobalActorAttributes(SourceLoc loc, CustomAttrOwner owner,
                            ArrayRef<CustomAttr *> attrs);
 
 /// Get the explicit global actor specified for a closure.
diff --git a/lib/Sema/TypeCheckPropertyWrapper.cpp b/lib/Sema/TypeCheckPropertyWrapper.cpp
index ed8dbea775570..e51fe485e9c7d 100644
--- a/lib/Sema/TypeCheckPropertyWrapper.cpp
+++ b/lib/Sema/TypeCheckPropertyWrapper.cpp
@@ -443,7 +443,7 @@ AttachedPropertyWrappersRequest::evaluate(Evaluator &evaluator,
     auto mutableAttr = const_cast<CustomAttr *>(attr);
     // Figure out which nominal declaration this custom attribute refers to.
     auto *nominal = evaluateOrDefault(
-      ctx.evaluator, CustomAttrNominalRequest{mutableAttr, dc}, nullptr);
+      ctx.evaluator, CustomAttrNominalRequest{mutableAttr, var}, nullptr);
 
     // If we didn't find a nominal type with a @propertyWrapper attribute,
     // skip this custom attribute.
diff --git a/lib/Sema/TypeCheckRequestFunctions.cpp b/lib/Sema/TypeCheckRequestFunctions.cpp
index ec0ecf94003c2..147c32c6758aa 100644
--- a/lib/Sema/TypeCheckRequestFunctions.cpp
+++ b/lib/Sema/TypeCheckRequestFunctions.cpp
@@ -184,7 +184,7 @@ AttachedResultBuilderRequest::evaluate(Evaluator &evaluator,
     auto mutableAttr = const_cast<CustomAttr *>(attr);
     // Figure out which nominal declaration this custom attribute refers to.
     auto *nominal = evaluateOrDefault(ctx.evaluator,
-                                      CustomAttrNominalRequest{mutableAttr, dc},
+                                      CustomAttrNominalRequest{mutableAttr, decl},
                                       nullptr);
 
     if (!nominal)
diff --git a/lib/Sema/TypeCheckType.cpp b/lib/Sema/TypeCheckType.cpp
index b49c5ba34a9cb..8193c3e773b81 100644
--- a/lib/Sema/TypeCheckType.cpp
+++ b/lib/Sema/TypeCheckType.cpp
@@ -35,6 +35,7 @@
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
+#include "swift/AST/NameLookupRequests.h"
 #include "swift/AST/PackExpansionMatcher.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/PrettyStackTrace.h"
diff --git a/test/attr/accessibility_print.swift b/test/attr/accessibility_print.swift
index c4ac2b916e1bd..315b96b247729 100644
--- a/test/attr/accessibility_print.swift
+++ b/test/attr/accessibility_print.swift
@@ -53,7 +53,6 @@ public struct BE_PublicStructPrivateMembers {
   // CHECK: private{{(\*/)?}} var x
   private var x = 0
   // CHECK: internal init()
-  // CHECK: private init(x: Int = 0)
 } // CHECK: {{^[}]}}
 
 // CHECK-LABEL: {{^}}fileprivate{{(\*/)?}} struct BF_FilePrivateStruct {