[PropertyWrappers] Fix a bug with class property wrapper access control (#29023)

* [PropertyWrappers] Class property wrapper cannot have an open init, so make sure to consider that when looking for suitable wrapper inits

* [PropertyWrappers] Extract the access control check into a separate static method

Author: theblixguy

lib/Sema/TypeCheckPropertyWrapper.cpp

@@ -36,6 +36,12 @@ enum class PropertyWrapperInitKind {
   Default
 };
 
+static bool isDeclNotAsAccessibleAsParent(ValueDecl *decl,
+                                          NominalTypeDecl *parent) {
+  return decl->getFormalAccess() <
+         std::min(parent->getFormalAccess(), AccessLevel::Public);
+}
+
 /// Find the named property in a property wrapper to which access will
 /// be delegated.
 static VarDecl *findValueProperty(ASTContext &ctx, NominalTypeDecl *nominal,
@@ -79,7 +85,7 @@ static VarDecl *findValueProperty(ASTContext &ctx, NominalTypeDecl *nominal,
 
   // The property must be as accessible as the nominal type.
   VarDecl *var = vars.front();
-  if (var->getFormalAccess() < nominal->getFormalAccess()) {
+  if (isDeclNotAsAccessibleAsParent(var, nominal)) {
     var->diagnose(diag::property_wrapper_type_requirement_not_accessible,
                   var->getFormalAccess(), var->getDescriptiveKind(),
                   var->getFullName(), nominal->getDeclaredType(),
@@ -157,7 +163,7 @@ findSuitableWrapperInit(ASTContext &ctx, NominalTypeDecl *nominal,
     }
 
     // Check accessibility.
-    if (init->getFormalAccess() < nominal->getFormalAccess()) {
+    if (isDeclNotAsAccessibleAsParent(init, nominal)) {
       nonviable.push_back(
           std::make_tuple(init, NonViableReason::Inaccessible, Type()));
       continue;
@@ -273,7 +279,7 @@ static SubscriptDecl *findEnclosingSelfSubscript(ASTContext &ctx,
 
   auto subscript = subscripts.front();
   // the subscript must be as accessible as the nominal type.
-  if (subscript->getFormalAccess() < nominal->getFormalAccess()) {
+  if (isDeclNotAsAccessibleAsParent(subscript, nominal)) {
     subscript->diagnose(diag::property_wrapper_type_requirement_not_accessible,
                         subscript->getFormalAccess(),
                         subscript->getDescriptiveKind(),

test/decl/var/property_wrappers.swift

@@ -1870,3 +1870,13 @@ struct Rdar57411331 {
 
   var other: Int
 }
+
+// SR-11994
+@propertyWrapper
+open class OpenPropertyWrapperWithPublicInit {
+  public init(wrappedValue: String) { // Okay
+    self.wrappedValue = wrappedValue
+  }
+  
+  open var wrappedValue: String = "Hello, world"
+}