[SE-0258] More tests and hardening for property wrapper composition

Author: DougGregor

lib/Sema/CSSimplify.cpp

@@ -4662,7 +4662,8 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyMemberConstraint(
 
       // If the base type is optional because we haven't chosen to force an
       // implicit optional, don't try to fix it. The IUO will be forced instead.
-      if (auto dotExpr = dyn_cast<UnresolvedDotExpr>(locator->getAnchor())) {
+      if (auto dotExpr =
+              dyn_cast_or_null<UnresolvedDotExpr>(locator->getAnchor())) {
         auto baseExpr = dotExpr->getBase();
         auto resolvedOverload = getResolvedOverloadSets();
         while (resolvedOverload) {
@@ -4682,8 +4683,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyMemberConstraint(
       auto innerTV = createTypeVariable(locator,
                                         TVO_CanBindToLValue |
                                         TVO_CanBindToNoEscape);
-      Type optTy = getTypeChecker().getOptionalType(
-          locator->getAnchor()->getSourceRange().Start, innerTV);
+      Type optTy = getTypeChecker().getOptionalType(SourceLoc(), innerTV);
       SmallVector<Constraint *, 2> optionalities;
       auto nonoptionalResult = Constraint::createFixed(
           *this, ConstraintKind::Bind,

test/decl/var/property_wrappers.swift

@@ -799,15 +799,30 @@ struct WrapperC<Value> {
   }
 }
 
+@propertyWrapper
+struct WrapperD<Value, X, Y> { // expected-note{{property wrapper type 'WrapperD' declared here}}
+  var value: Value
+}
+
+@propertyWrapper
+struct WrapperE<Value> {
+  var value: Value
+}
+
 struct TestComposition {
   @WrapperA @WrapperB @WrapperC var p1: Int?
   @WrapperA @WrapperB @WrapperC var p2 = "Hello"
+  @WrapperD<WrapperE, Int, String> @WrapperE var p3: Int?
+  @WrapperD<WrapperC, Int, String> @WrapperC var p4: Int?
+  @WrapperD<WrapperC, Int, String> @WrapperE var p5: Int // expected-error{{property type 'Int' does not match that of the 'value' property of its wrapper type 'WrapperD<WrapperC, Int, String>'}}
 
 	func triggerErrors(d: Double) {
 		p1 = d // expected-error{{cannot assign value of type 'Double' to type 'Int?'}}
 		p2 = d // expected-error{{cannot assign value of type 'Double' to type 'String?'}}
+    p3 = d // expected-error{{cannot assign value of type 'Double' to type 'Int?'}}
 
 		$p1 = d // expected-error{{cannot assign value of type 'Double' to type 'WrapperA<WrapperB<WrapperC<Int>>>'}}
 		$p2 = d // expected-error{{cannot assign value of type 'Double' to type 'WrapperA<WrapperB<WrapperC<String>>>'}}
+    $p3 = d // expected-error{{cannot assign value of type 'Double' to type 'WrapperD<WrapperE<Int?>, Int, String>'}}
 	}
 }