Compile and run Hello World!

pkg/compiler/lib/src/kernel/element_map_impl.dart

 // Copyright (c) 2017, 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.
 
 library dart2js.kernel.element_map;
 
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/clone.dart';
 import 'package:kernel/type_algebra.dart';
 
@@ skipping 662 matching lines @@
   ClassEntity getClass(ir.Class node) => _getClass(node);
 
   @override
   FieldEntity getField(ir.Field node) => _getField(node);
 
   bool hasConstantFieldInitializer(KField field) {
     _FieldData data = _memberList[field.memberIndex];
     return getFieldConstantValue(data.node) != null;
   }
 
+  ConstantValue getConstantFieldInitializer(KField field) {
+    _FieldData data = _memberList[field.memberIndex];
+    ConstantValue value = getFieldConstantValue(data.node);
+    assert(value != null,
+        failedAt(field, "Field $field doesn't have a constant initial value."));
+    return value;
+  }
+
   TypeVariableEntity getTypeVariable(ir.TypeParameter node) =>
       _getTypeVariable(node);
 
   @override
   FunctionEntity getMethod(ir.Procedure node) => _getMethod(node);
 
   void forEachParameter(KFunction function,
       void f(DartType type, String name, ConstantValue defaultValue)) {
     _FunctionData data = _memberList[function.memberIndex];
     data.forEachParameter(this, f);
@@ skipping 1170 matching lines @@
   @override
   DiagnosticReporter get reporter {
     return _elementMap.reporter;
   }
 
   @override
   ConstantValue getFieldConstantValue(ir.Field field) {
     throw new UnsupportedError("JsKernelToElementMap.getFieldConstantValue");
   }
 }