#1400. Add inline classes members override test (#2085)

Author: sgrekhov

LanguageFeatures/Inline-classes/composing_inline_classes_A05_t06.dart

@@ -0,0 +1,86 @@
+// Copyright (c) 2023, 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 Assume that DV is an inline class declaration named Inline, and
+/// V1 occurs as one of the <type>s in the <interfaces> of DV. In this case we
+/// say that V1 is a superinterface of DV.
+/// ...
+/// A compile-time error occurs if an inline class declaration DV has two
+/// superinterfaces V1 and V2, where both V1 and V2 have a member named m, and
+/// the two declarations of m are distinct declarations, and DV does not declare
+/// a member named m.
+///
+/// @description Checks that it is no an error if an inline class declaration
+/// `DV` has superinterface `V` with member `m` and redeclares this member even
+/// this is not a correct override for a regular class
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "../../Utils/expect.dart";
+
+String log = "";
+
+inline class V {
+  final int id;
+  V(this.id);
+
+  int foo() => 0;
+  int bar(num n) => 0;
+  void set setter(num i) {
+    log += "V.setter=";
+  }
+}
+
+inline class C1 implements V {
+  final int id;
+  C1(this.id);
+
+  num foo() => 1;
+  int bar(int n) => 1;
+  void set setter(int i) {
+    log += "C1.setter=";
+  }
+}
+
+inline class C2 implements V {
+  final int id;
+  C2(this.id);
+
+  int get foo => 2;
+  String get bar => "2";
+  void set setter(String s) {
+    log += "C2.setter=";
+  }
+}
+
+main() {
+  V v1 = C1(0);
+  Expect.equals(0, v1.foo());
+  Expect.equals(0, v1.bar(3.14));
+  v1.setter = 1;
+  Expect.equals("V.setter=", log);
+  log = "";
+
+  V v2 = C2(0);
+  Expect.equals(0, v2.foo());
+  Expect.equals(0, v2.bar(3.14));
+  v2.setter = 1;
+  Expect.equals("V.setter=", log);
+  log = "";
+
+  C1 c1 = C1(0);
+  Expect.equals(1, c1.foo());
+  Expect.equals(1, c1.bar(42));
+  c1.setter = 1;
+  Expect.equals("C1.setter=", log);
+  log = "";
+
+  C2 c2 = C2(0);
+  Expect.equals(2, c2.foo);
+  Expect.equals("2", c2.bar);
+  c2.setter = "1";
+  Expect.equals("C2.setter=", log);
+  log = "";
+}