#993. Tests for not external members of Struct subtype added

LibTest/ffi/Struct/Struct_A08_t01.dart

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+/**
+ * @assertion All field declarations in a Struct subclass declaration must be
+ * marked external. You cannot create instances of the class, only have it point
+ * to existing native memory, so there is no memory in which to store non-native
+ * fields. External fields also cannot be initialized by constructors since no
+ * Dart object is being created.
+ *
+ * @description Checks that all field declarations in a Struct subclass
+ * declaration must be marked external
+ * @author sgrekhov@unipro.ru
+ * @issue 45293
+ */
+import "dart:ffi";
+import "package:ffi/ffi.dart";
+
+class S1 extends Struct {
+  @Int16()
+  int? i;
+//^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+void main() {
+  Pointer<S1> p = calloc<S1>();
+  S1 s1 = p.ref;
+  print(s1.i);
+}

LibTest/ffi/Struct/Struct_A08_t02.dart

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+/**
+ * @assertion All field declarations in a Struct subclass declaration must be
+ * marked external. You cannot create instances of the class, only have it point
+ * to existing native memory, so there is no memory in which to store non-native
+ * fields. External fields also cannot be initialized by constructors since no
+ * Dart object is being created.
+ *
+ * @description Checks that all field declarations in a Struct subclass
+ * declaration must be marked external
+ * @author sgrekhov@unipro.ru
+ * @issue 45293
+ */
+import "dart:ffi";
+import "package:ffi/ffi.dart";
+
+class S1 extends Struct {
+  @Double()
+  double? d;
+//^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+void main() {
+  Pointer<S1> p = calloc<S1>();
+  S1 s1 = p.ref;
+  print(s1.d);
+}

LibTest/ffi/Struct/Struct_A08_t03.dart

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+/**
+ * @assertion All field declarations in a Struct subclass declaration must be
+ * marked external. You cannot create instances of the class, only have it point
+ * to existing native memory, so there is no memory in which to store non-native
+ * fields. External fields also cannot be initialized by constructors since no
+ * Dart object is being created.
+ *
+ * @description Checks that all field declarations in a Struct subclass
+ * declaration must be marked external
+ * @author sgrekhov@unipro.ru
+ * @issue 45293
+ */
+import "dart:ffi";
+import "package:ffi/ffi.dart";
+
+class S1 extends Struct {
+  Pointer<S1>? next;
+//^^^^^^^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+void main() {
+  Pointer<S1> p = calloc<S1>();
+  S1 s1 = p.ref;
+  print(s1.next);
+}