[Sema] Propagate nonisolated attribute from wrapped variable to the synthesized projectedValue variable

Author: theblixguy

lib/Sema/TypeCheckStorage.cpp

@@ -2685,6 +2685,13 @@ static VarDecl *synthesizePropertyWrapperProjectionVar(
     var->getAttrs().add(
         new (ctx) ProjectedValuePropertyAttr(name, SourceLoc(), SourceRange(),
                                              /*Implicit=*/true));
+
+  // If the wrapped property has a nonisolated attribute, propagate it to
+  // the synthesized projectedValue as well.
+  if (var->getAttrs().getAttribute<NonisolatedAttr>()) {
+    property->getAttrs().add(new (ctx) NonisolatedAttr(/*Implicit=*/true));
+  }
+
   return property;
 }