[Property Wrappers] Let PropertyWrapperBackingPropertyTypeRequest

handle all errors with a property wrapper backing type.

Author: hborla

lib/Sema/CSGen.cpp

@@ -4171,10 +4171,6 @@ bool ConstraintSystem::generateConstraints(
 
   case SolutionApplicationTarget::Kind::uninitializedWrappedVar: {
     auto *wrappedVar = target.getAsUninitializedWrappedVar();
-    Type propertyType = wrappedVar->getType();
-    if (propertyType->hasError())
-      return true;
-
     auto *outermostWrapper = wrappedVar->getAttachedPropertyWrappers().front();
     auto *typeRepr = outermostWrapper->getTypeRepr();
     auto backingType = openUnboundGenericTypes(outermostWrapper->getType(),
@@ -4183,6 +4179,9 @@ bool ConstraintSystem::generateConstraints(
 
     auto wrappedValueType =
         generateWrappedPropertyTypeConstraints(*this, backingType, wrappedVar);
+    Type propertyType = wrappedVar->getType();
+    if (!wrappedValueType || propertyType->hasError())
+      return true;
 
     addConstraint(ConstraintKind::Equal, propertyType, wrappedValueType,
         getConstraintLocator(wrappedVar, LocatorPathElt::ContextualType()));

lib/Sema/TypeCheckPropertyWrapper.cpp

@@ -577,9 +577,6 @@ PropertyWrapperBackingPropertyTypeRequest::evaluate(
   if (!rawType || rawType->hasError())
     return Type();
 
-  if (!rawType->hasUnboundGenericType())
-    return rawType->mapTypeOutOfContext();
-
   auto binding = var->getParentPatternBinding();
   if (!binding)
     return Type();

lib/Sema/TypeCheckStorage.cpp

@@ -2605,27 +2605,6 @@ PropertyWrapperBackingPropertyInfoRequest::evaluate(Evaluator &evaluator,
   Type storageInterfaceType = wrapperType;
   Type storageType = dc->mapTypeIntoContext(storageInterfaceType);
 
-  // Make sure that the property type matches the value of the
-  // wrapper type.
-  if (!storageInterfaceType->hasError()) {
-    Type expectedPropertyType =
-        computeWrappedValueType(var, storageInterfaceType);
-    Type propertyType = var->getValueInterfaceType();
-    assert(propertyType);
-    if (!expectedPropertyType->hasError() &&
-        !propertyType->hasError() &&
-        !propertyType->isEqual(expectedPropertyType)) {
-      var->diagnose(diag::property_wrapper_incompatible_property,
-                    propertyType, wrapperType);
-      var->setInvalid();
-      if (auto nominalWrapper = wrapperType->getAnyNominal()) {
-        nominalWrapper->diagnose(diag::property_wrapper_declared_here,
-                                 nominalWrapper->getName());
-      }
-      return PropertyWrapperBackingPropertyInfo();
-    }
-  }
-
   // Create the backing storage property and note it in the cache.
   VarDecl *backingVar = new (ctx) VarDecl(/*IsStatic=*/var->isStatic(),
                                           VarDecl::Introducer::Var,

test/decl/var/property_wrappers.swift

@@ -958,12 +958,12 @@ struct UsesWrapperRequiringP {
 
 // SR-10899 / rdar://problem/51588022
 @propertyWrapper
-struct SR_10899_Wrapper { // expected-note{{property wrapper type 'SR_10899_Wrapper' declared here}}
+struct SR_10899_Wrapper {
   var wrappedValue: String { "hi" }
 }
 
 struct SR_10899_Usage {
-  @SR_10899_Wrapper var thing: Bool // expected-error{{property type 'Bool' does not match that of the 'wrappedValue' property of its wrapper type 'SR_10899_Wrapper'}}
+  @SR_10899_Wrapper var thing: Bool // expected-error{{property type 'Bool' does not match 'wrappedValue' type 'String'}}
 }
 
 // SR-11061 / rdar://problem/52593304 assertion with DeclContext mismatches