[Sema] TypeWrappers: Implement @typeWrapperIgnored checking

Author: xedin

lib/Sema/CodeSynthesis.cpp

@@ -385,8 +385,12 @@ static ConstructorDecl *createImplicitConstructor(NominalTypeDecl *decl,
         if (var->isImplicit())
           continue;
 
-        // Computed properties are not included.
-        if (!var->hasStorage())
+        // Computed properties are not included, except in cases
+        // where property has a property wrapper and `@typeWrapperIgnored`
+        // attribute.
+        if (!var->hasStorage() &&
+            !(var->hasAttachedPropertyWrapper() &&
+              var->getAttrs().hasAttribute<TypeWrapperIgnoredAttr>()))
           continue;
 
         // If this is a memberwise initializeable property include

lib/Sema/TypeCheckTypeWrapper.cpp

@@ -315,6 +315,11 @@ bool IsPropertyAccessedViaTypeWrapper::evaluate(Evaluator &evaluator,
   if (property->isStatic() || property->isLet())
     return false;
 
+  // If this property has `@typeWrapperIgnored` attribute
+  // it should not be managed by a type wrapper.
+  if (property->getAttrs().hasAttribute<TypeWrapperIgnoredAttr>())
+    return false;
+
   // `lazy` properties are not wrapped.
   if (property->getAttrs().hasAttribute<LazyAttr>() ||
       property->isLazyStorageProperty())
@@ -337,9 +342,13 @@ bool IsPropertyAccessedViaTypeWrapper::evaluate(Evaluator &evaluator,
     // This is the only thing that wrapper needs to handle because
     // all access to the wrapped variable and it's projection
     // is routed through it.
-    if (property->getOriginalWrappedProperty(
-          PropertyWrapperSynthesizedPropertyKind::Backing))
-      return true;
+    if (auto *wrappedProperty = property->getOriginalWrappedProperty(
+            PropertyWrapperSynthesizedPropertyKind::Backing)) {
+      // If wrapped property is ignored - its backing storage is
+      // ignored as well.
+      return !wrappedProperty->getAttrs()
+                  .hasAttribute<TypeWrapperIgnoredAttr>();
+    }
   }
 
   // Don't wrap any compiler synthesized properties except to

test/Interpreter/Inputs/type_wrapper_defs.swift

@@ -146,3 +146,10 @@ public class ClassWithDesignatedInit {
     $_storage = .init(memberwise: $Storage(a: 42, _b: PropWrapperWithoutInit(value: b)))
   }
 }
+
+@Wrapper
+public class PersonWithIgnoredAge {
+  public var name: String
+  @typeWrapperIgnored public var age: Int = 0
+  @typeWrapperIgnored @PropWrapper public var manufacturer: String?
+}

test/Interpreter/type_wrappers.swift

@@ -408,3 +408,44 @@ do {
   // CHECK: in getter
   // CHECK-NEXT: [42]
 }
+
+do {
+  var arthur = PersonWithIgnoredAge(name: "Arthur Dent", age: 30)
+  // CHECK: Wrapper.init($Storage(name: "Arthur Dent"))
+
+  print(arthur.name)
+  // CHECK: in getter
+  // CHECK-NEXT: Arthur Dent
+
+  print(arthur.age)
+  // CHECK-NOT: in getter
+  // CHECK-NEXT: 30
+
+  print(arthur.manufacturer)
+  // CHECK-NOT: in getter
+  // CHECK-NEXT: nil
+
+  arthur.age = 32
+  // CHECK-NOT: in setter
+
+  var marvin = PersonWithIgnoredAge(name: "Marvin The Paranoid Android", manufacturer: "Sirius Cybernetics Corporation")
+  // CHECK: Wrapper.init($Storage(name: "Marvin The Paranoid Android"))
+
+  print(marvin.name)
+  // CHECK: in getter
+  // CHECK-NEXT: Marvin The Paranoid Android
+
+  print(marvin.age)
+  // CHECK-NOT: in getter
+  // CHECK-NEXT: 0
+
+  print(marvin.manufacturer)
+  // CHECK-NOT: in getter
+  // CHECK-NEXT: Sirius Cybernetics Corporation
+
+  marvin.age = 1000
+  // CHECK-NOT: in setter
+
+  marvin.manufacturer = nil
+  // CHECK-NOT: in setter
+}