Handle const Symbol(...) in kernel_impact

pkg/compiler/lib/src/ssa/kernel_impact.dart

 // Copyright (c) 2016, 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.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../common.dart';
 import '../common/names.dart';
 import '../compiler.dart';
 import '../constants/expressions.dart';
+import '../constants/values.dart';
 import '../common_elements.dart';
 import '../elements/types.dart';
 import '../elements/elements.dart' show AstElement, ResolvedAst;
 import '../elements/entities.dart';
 import '../js_backend/backend.dart' show JavaScriptBackend;
 import '../kernel/element_adapter.dart';
 import '../kernel/kernel.dart';
 import '../resolution/registry.dart' show ResolutionWorldImpactBuilder;
 import '../universe/call_structure.dart';
 import '../universe/feature.dart';
@@ skipping 252 matching lines @@
         target.enclosingClass, node.arguments.types);
     CallStructure callStructure =
         elementAdapter.getCallStructure(node.arguments);
     impactBuilder.registerStaticUse(isConst
         ? new StaticUse.constConstructorInvoke(constructor, callStructure, type)
         : new StaticUse.typedConstructorInvoke(
             constructor, callStructure, type));
     if (type.typeArguments.any((DartType type) => !type.isDynamic)) {
       impactBuilder.registerFeature(Feature.TYPE_VARIABLE_BOUNDS_CHECK);
     }
+    if (isConst && commonElements.isSymbolConstructor(constructor)) {
+      ConstantValue value =
+          elementAdapter.getConstantValue(node.arguments.positional.first);
+      if (!value.isString) {
+        throw new SpannableAssertionFailure(
+            CURRENT_ELEMENT_SPANNABLE,
+            "Unexpected constant value in const Symbol(...) call: "
+            "${value.toStructuredText()}");
+      }
+      StringConstantValue stringValue = value;
+      impactBuilder
+          .registerConstSymbolName(stringValue.primitiveValue.slowToString());
+    }
   }
 
   @override
   void visitSuperInitializer(ir.SuperInitializer node) {
     ConstructorEntity target = elementAdapter.getConstructor(node.target);
     _visitArguments(node.arguments);
     impactBuilder.registerStaticUse(new StaticUse.superConstructorInvoke(
         target, elementAdapter.getCallStructure(node.arguments)));
   }
 
@@ skipping 286 matching lines @@
     ConstructorEntity target = elementAdapter.getConstructor(node.target);
     impactBuilder.registerStaticUse(new StaticUse.superConstructorInvoke(
         target, elementAdapter.getCallStructure(node.arguments)));
   }
 
   // TODO(johnniwinther): Make this throw and visit child nodes explicitly
   // instead to ensure that we don't visit unwanted parts of the ir.
   @override
   void defaultNode(ir.Node node) => node.visitChildren(this);
 }