[Property wrappers] Fix crash due to wrapped type/wrapper type confusion.

We had two predicates that were used to determine whether the default
argument for a wrapped property in the memberwise initializer would be
of the wrapper type (e.g., Lazy<Int>) vs. the wrapped type
(Int). Those two predicates could disagree, causing a SILGen assertion
and crash. Collapse the two predicates into one correct one,
fixing rdar://problem/57545381.

Author: DougGregor

include/swift/AST/Decl.h

@@ -5102,16 +5102,16 @@ class VarDecl : public AbstractStorageDecl {
   /// Retrieve the backing storage property for a lazy property.
   VarDecl *getLazyStorageProperty() const;
 
-  /// Whether this is a property with a property wrapper that was initialized
-  /// via a value of the original type, e.g.,
+  /// Whether the memberwise initializer parameter for a property with a
+  /// property wrapper type uses the wrapped type. This will occur, for example,
+  /// when there is an explicitly-specified initializer like:
   ///
   /// \code
   /// @Lazy var i = 17
   /// \end
-  bool isPropertyWrapperInitializedWithInitialValue() const;
-
-  /// Whether the memberwise initializer parameter for a property with a property wrapper type
-  /// uses the wrapped type.
+  ///
+  /// Or when there is no initializer but each composed property wrapper has
+  /// a suitable `init(initialValue:)`.
   bool isPropertyMemberwiseInitializedWithWrappedType() const;
 
   /// If this property is the backing storage for a property with an attached

lib/AST/Decl.cpp

@@ -5807,13 +5807,12 @@ VarDecl *VarDecl::getLazyStorageProperty() const {
       {});
 }
 
-static bool propertyWrapperInitializedViaInitialValue(
-   const VarDecl *var, bool checkDefaultInit) {
-  auto customAttrs = var->getAttachedPropertyWrappers();
+bool VarDecl::isPropertyMemberwiseInitializedWithWrappedType() const {
+  auto customAttrs = getAttachedPropertyWrappers();
   if (customAttrs.empty())
     return false;
 
-  auto *PBD = var->getParentPatternBinding();
+  auto *PBD = getParentPatternBinding();
   if (!PBD)
     return false;
 
@@ -5828,23 +5827,12 @@ static bool propertyWrapperInitializedViaInitialValue(
     return false;
 
   // Default initialization does not use a value.
-  if (checkDefaultInit &&
-      var->getAttachedPropertyWrapperTypeInfo(0).defaultInit)
+  if (getAttachedPropertyWrapperTypeInfo(0).defaultInit)
     return false;
 
   // If all property wrappers have an initialValue initializer, the property
   // wrapper will be initialized that way.
-  return var->allAttachedPropertyWrappersHaveInitialValueInit();
-}
-
-bool VarDecl::isPropertyWrapperInitializedWithInitialValue() const {
-  return propertyWrapperInitializedViaInitialValue(
-      this, /*checkDefaultInit=*/true);
-}
-
-bool VarDecl::isPropertyMemberwiseInitializedWithWrappedType() const {
-  return propertyWrapperInitializedViaInitialValue(
-      this, /*checkDefaultInit=*/false);
+  return allAttachedPropertyWrappersHaveInitialValueInit();
 }
 
 Identifier VarDecl::getObjCPropertyName() const {

lib/SIL/TypeLowering.cpp

@@ -1887,7 +1887,7 @@ static CanAnyFunctionType getStoredPropertyInitializerInterfaceType(
   // wrapper that was initialized with '=', the stored property initializer
   // will be in terms of the original property's type.
   if (auto originalProperty = VD->getOriginalWrappedProperty()) {
-    if (originalProperty->isPropertyWrapperInitializedWithInitialValue())
+    if (originalProperty->isPropertyMemberwiseInitializedWithWrappedType())
       resultTy = originalProperty->getValueInterfaceType()->getCanonicalType();
   }
 

lib/SILGen/SILGenConstructor.cpp

@@ -899,7 +899,7 @@ static Type getInitializationTypeInContext(
   // initialization type is the original property type.
   if (auto singleVar = pattern->getSingleVar()) {
     if (auto originalProperty = singleVar->getOriginalWrappedProperty()) {
-      if (originalProperty->isPropertyWrapperInitializedWithInitialValue())
+      if (originalProperty->isPropertyMemberwiseInitializedWithWrappedType())
         interfaceType = originalProperty->getValueInterfaceType();
     }
   }
@@ -968,7 +968,7 @@ void SILGenFunction::emitMemberInitializers(DeclContext *dc,
         if (auto singleVar = pbd->getSingleVar()) {
           auto originalVar = singleVar->getOriginalWrappedProperty();
           if (originalVar &&
-              originalVar->isPropertyWrapperInitializedWithInitialValue()) {
+              originalVar->isPropertyMemberwiseInitializedWithWrappedType()) {
             result = maybeEmitPropertyWrapperInitFromValue(
                 *this, init, singleVar, std::move(result));
           }

lib/SILGen/SILGenFunction.cpp

@@ -812,7 +812,7 @@ void SILGenFunction::emitGeneratorFunction(SILDeclRef function, VarDecl *var) {
   // wrapper that was initialized with '=', the stored property initializer
   // will be in terms of the original property's type.
   if (auto originalProperty = var->getOriginalWrappedProperty()) {
-    if (originalProperty->isPropertyWrapperInitializedWithInitialValue()) {
+    if (originalProperty->isPropertyMemberwiseInitializedWithWrappedType()) {
       interfaceType = originalProperty->getValueInterfaceType();
       varType = originalProperty->getType();
     }

test/SILGen/property_wrappers.swift

@@ -541,6 +541,35 @@ struct SR_11603 {
   }
 }
 
+// rdar://problem/57545381 - crash due to inconsistent decision about whether
+// to initialize a wrapper property with an instance of the wrapper type vs.
+// the wrapped type.
+@propertyWrapper
+class WrappedInt {
+  var intValue: Int?
+
+  var wrappedValue: Int? {
+    get {
+      return intValue
+    }
+    set {
+      intValue = newValue
+    }
+  }
+
+  init() { }
+
+  init(wrappedValue: Int?) {
+    self.wrappedValue = wrappedValue
+  }
+}
+
+struct WrappedIntContainer {
+  // CHECK: sil hidden [ossa] @$s17property_wrappers19WrappedIntContainerV3intAcA0cD0C_tcfcfA_ : $@convention(thin) () -> @owned WrappedInt
+  @WrappedInt var int: Int?
+}
+
+
 // CHECK-LABEL: sil_vtable ClassUsingWrapper {
 // CHECK-NEXT:  #ClassUsingWrapper.x!getter.1: (ClassUsingWrapper) -> () -> Int : @$s17property_wrappers17ClassUsingWrapperC1xSivg   // ClassUsingWrapper.x.getter
 // CHECK-NEXT:  #ClassUsingWrapper.x!setter.1: (ClassUsingWrapper) -> (Int) -> () : @$s17property_wrappers17ClassUsingWrapperC1xSivs // ClassUsingWrapper.x.setter