Use failedAt in more places

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';
@@ skipping 136 matching lines @@
       case ir.AsyncMarker.SyncStar:
         impactBuilder.registerFeature(Feature.SYNC_STAR);
         break;
       case ir.AsyncMarker.Async:
         impactBuilder.registerFeature(Feature.ASYNC);
         break;
       case ir.AsyncMarker.AsyncStar:
         impactBuilder.registerFeature(Feature.ASYNC_STAR);
         break;
       case ir.AsyncMarker.SyncYielding:
-        throw new SpannableAssertionFailure(CURRENT_ELEMENT_SPANNABLE,
+        failedAt(CURRENT_ELEMENT_SPANNABLE,
             "Unexpected async marker: ${asyncMarker}");
     }
   }
 
   ResolutionImpact buildProcedure(ir.Procedure procedure) {
     handleSignature(procedure.function);
     visitNode(procedure.function.body);
     handleAsyncMarker(procedure.function.asyncMarker);
     if (procedure.isExternal &&
         !elementAdapter.isForeignLibrary(procedure.enclosingLibrary)) {
@@ skipping 124 matching lines @@
         ? 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(
+        failedAt(
             CURRENT_ELEMENT_SPANNABLE,
             "Unexpected constant value in const Symbol(...) call: "
             "${value.toStructuredText()}");
       }
       StringConstantValue stringValue = value;
       impactBuilder.registerConstSymbolName(stringValue.primitiveValue);
     }
   }
 
   @override
@@ skipping 299 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);
 }