Merge pull request swiftlang#27139 from DougGregor/Self-in-lazy-init

Author: swift-ci

lib/Sema/CSGen.cpp

@@ -2478,11 +2478,11 @@ namespace {
     }
 
     Type visitDefaultArgumentExpr(DefaultArgumentExpr *expr) {
-      llvm_unreachable("Already type checked");
+      return expr->getType();
     }
 
     Type visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *expr) {
-      llvm_unreachable("Already type checked");
+      return expr->getType();
     }
 
     Type visitApplyExpr(ApplyExpr *expr) {

lib/Sema/ConstraintSystem.cpp

@@ -2880,6 +2880,9 @@ ConstraintSystem::getArgumentInfoLocator(ConstraintLocator *locator) {
 
 Optional<ConstraintSystem::ArgumentInfo>
 ConstraintSystem::getArgumentInfo(ConstraintLocator *locator) {
+  if (!locator)
+    return None;
+
   if (auto *infoLocator = getArgumentInfoLocator(locator)) {
     auto known = ArgumentInfos.find(infoLocator);
     if (known != ArgumentInfos.end())

lib/Sema/TypeCheckCaptures.cpp

@@ -645,6 +645,12 @@ void TypeChecker::computeCaptures(AnyFunctionRef AFR) {
   }
 }
 
+static bool isLazy(PatternBindingDecl *PBD) {
+  if (auto var = PBD->getSingleVar())
+    return var->getAttrs().hasAttribute<LazyAttr>();
+  return false;
+}
+
 void TypeChecker::checkPatternBindingCaptures(NominalTypeDecl *typeDecl) {
   auto &ctx = typeDecl->getASTContext();
 
@@ -669,7 +675,7 @@ void TypeChecker::checkPatternBindingCaptures(NominalTypeDecl *typeDecl) {
                               /*ObjC=*/false);
       init->walk(finder);
 
-      if (finder.getDynamicSelfCaptureLoc().isValid()) {
+      if (finder.getDynamicSelfCaptureLoc().isValid() && !isLazy(PBD)) {
         ctx.Diags.diagnose(finder.getDynamicSelfCaptureLoc(),
                            diag::dynamic_self_stored_property_init);
       }

test/type/self.swift

@@ -253,4 +253,13 @@ class SelfStoredPropertyInit {
   static func myValue() -> Int { return 123 }
 
   var value = Self.myValue() // expected-error {{covariant 'Self' type cannot be referenced from a stored property initializer}}
-}
+}
+
+// rdar://problem/55273931 - erroneously rejecting 'Self' in lazy initializer
+class Foo {
+  static var value: Int = 17
+
+  lazy var doubledValue: Int = {
+    Self.value * 2
+  }()
+}