Demonstrate bug for the VMs way of doing initializers in face of mixins

See http://dartbug.com/34841#issuecomment-458917175
and test in this CL for explanation.

Change-Id: Ie1d15078a9c5f71aa6edacd792b440520a3eb877
Reviewed-on: https://dart-review.googlesource.com/c/91660
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Peter von der Ahé <ahe@google.com>

runtime/observatory/tests/service/regress_34841_lib.dart

@@ -0,0 +1,9 @@
+// Copyright (c) 2019, 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.
+
+class Foo {
+  final String foo = () {
+    return StackTrace.current.toString();
+  }();
+}

runtime/observatory/tests/service/regress_34841_test.dart

@@ -0,0 +1,68 @@
+// Copyright (c) 2019, 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.
+
+// While it's not (currently) necessary, add some noise here to push down token
+// positions in this file compared to the file regress_34841_lib.dart.
+// This is to ensure that any possible tokens in that file are just comments
+// (i.e. not actual) positions in this file.
+
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+import 'service_test_common.dart';
+import 'dart:developer';
+import 'regress_34841_lib.dart';
+
+class Bar extends Object with Foo {}
+
+void testFunction() {
+  Bar bar = new Bar();
+  print(bar.foo);
+  debugger();
+}
+
+var tests = <IsolateTest>[
+  hasStoppedAtBreakpoint,
+  (Isolate isolate) async {
+    var stack = await isolate.getStack();
+
+    // Make sure we are in the right place.
+    expect(stack.type, equals('Stack'));
+    expect(stack['frames'].length, greaterThanOrEqualTo(1));
+    expect(stack['frames'][0].function.name, equals('testFunction'));
+
+    var root = isolate.rootLibrary;
+    await root.load();
+    Script script = root.scripts.first;
+    await script.load();
+
+    var params = {
+      'reports': ['Coverage'],
+      'scriptId': script.id,
+      'forceCompile': true
+    };
+    var report = await isolate.invokeRpcNoUpgrade('getSourceReport', params);
+    List<dynamic> ranges = report['ranges'];
+    List<int> coveragePlaces = <int>[];
+    for (var range in ranges) {
+      for (int i in range["coverage"]["hits"]) {
+        coveragePlaces.add(i);
+      }
+      for (int i in range["coverage"]["misses"]) {
+        coveragePlaces.add(i);
+      }
+    }
+
+    // Make sure we can translate it all.
+    for (int place in coveragePlaces) {
+      int line = script.tokenToLine(place);
+      int column = script.tokenToCol(place);
+      if (line == null || column == null) {
+        throw "Token $place translated to $line:$column";
+      }
+    }
+  },
+];
+
+main(args) => runIsolateTests(args, tests, testeeConcurrent: testFunction);

runtime/observatory/tests/service/service_kernel.status

@@ -46,6 +46,7 @@ evaluate_activation_in_method_class_test: RuntimeError # Issue 35505
 evaluate_activation_test/instance: RuntimeError # http://dartbug.com/20047
 evaluate_activation_test/scope: RuntimeError # http://dartbug.com/20047
 pause_on_unhandled_async_exceptions2_test: Pass, Slow
+regress_34841_test: RuntimeError # http://dartbug.com/34841
 unused_changes_in_last_reload_test: RuntimeError
 
 [ $compiler == dartkp ]