Sema: Make implicit elementwise struct init insensitive to lazy validation order.

lib/Sema/CodeSynthesis.cpp

@@ -1881,12 +1881,21 @@ ConstructorDecl *swift::createImplicitConstructor(TypeChecker &tc,
   if (ICK == ImplicitConstructorKind::Memberwise) {
     assert(isa<StructDecl>(decl) && "Only struct have memberwise constructor");
 
-    // Computed and static properties are not initialized.
-    for (auto var : decl->getStoredProperties()) {
-      if (var->isImplicit())
+    for (auto member : decl->getMembers()) {
+      auto var = dyn_cast<VarDecl>(member);
+      if (!var)
         continue;
-      tc.validateDecl(var);
 
+      // Implicit, computed, and static properties are not initialized.
+      // The exception is lazy properties, which due to batch mode we may or
+      // may not have yet finalized, so they may currently be "stored" or
+      // "computed" in the current AST state.
+      if (var->isImplicit() || var->isStatic())
+        continue;
+      tc.validateDecl(var);
+      if (!var->hasStorage() && !var->getAttrs().hasAttribute<LazyAttr>())
+        continue;
+
       // Initialized 'let' properties have storage, but don't get an argument
       // to the memberwise initializer since they already have an initial
       // value that cannot be overridden.

test/decl/var/Inputs/lazy_properties_batch_mode_b.swift

@@ -0,0 +1,7 @@
+struct B {
+  var other: Int = 0
+  lazy var crash: String = {
+    return ""
+  }()
+}
+

test/decl/var/lazy_properties_batch_mode.swift

@@ -0,0 +1,4 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -c -primary-file %s -o %t/a.o -primary-file %S/Inputs/lazy_properties_batch_mode_b.swift -o %t/b.o
+func foo(_: B) {}
+