Use failedAt in more places

pkg/compiler/lib/src/kernel/env.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.env;
 
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/clone.dart';
 import 'package:kernel/type_algebra.dart';
 
@@ skipping 106 matching lines @@
             _setterMap[member.name.name] = member;
           } else {
             _memberMap[member.name.name] = member;
           }
         } else if (member is ir.Field) {
           _memberMap[member.name.name] = member;
           if (member.isMutable) {
             _setterMap[member.name.name] = member;
           }
         } else {
-          throw new SpannableAssertionFailure(
+          failedAt(
               NO_LOCATION_SPANNABLE, "Unexpected library member node: $member");
         }
       }
     }
   }
 
   /// Return the [ir.Member] for the member [name] in [library].
   ir.Member lookupMember(String name, {bool setter: false}) {
     _ensureMemberMaps();
     return setter ? _setterMap[name] : _memberMap[name];
@@ skipping 122 matching lines @@
               _memberMap[member.name.name] = member;
             }
           } else if (member is ir.Field) {
             if (!includeStatic && member.isStatic) continue;
             _memberMap[member.name.name] = member;
             if (member.isMutable) {
               _setterMap[member.name.name] = member;
             }
             _memberMap[member.name.name] = member;
           } else {
-            throw new SpannableAssertionFailure(
+            failedAt(
                 NO_LOCATION_SPANNABLE, "Unexpected class member node: $member");
           }
         }
       }
 
       if (cls.mixedInClass != null) {
         addMembers(cls.mixedInClass, includeStatic: false);
       }
       addMembers(cls, includeStatic: true);
 
@@ skipping 139 matching lines @@
   ConstructorData(ir.Member node, ir.FunctionNode functionNode)
       : super(node, functionNode);
 
   ConstantConstructor getConstructorConstant(
       KernelToElementMapBase elementMap, ConstructorEntity constructor) {
     if (_constantConstructor == null) {
       if (node is ir.Constructor && constructor.isConst) {
         _constantConstructor =
             new Constantifier(elementMap).computeConstantConstructor(node);
       } else {
-        throw new SpannableAssertionFailure(
+        failedAt(
             constructor,
             "Unexpected constructor $constructor in "
             "KernelWorldBuilder._getConstructorConstant");
       }
     }
     return _constantConstructor;
   }
 
   @override
   ConstructorData copy() {
     return new ConstructorData(node, functionNode);
   }
 }
 
 class FieldData extends MemberData {
   ConstantExpression _constant;
 
   FieldData(ir.Field node) : super(node);
 
   ir.Field get node => super.node;
 
   ConstantExpression getFieldConstant(
       KernelToElementMapBase elementMap, FieldEntity field) {
     if (_constant == null) {
       if (node.isConst) {
         _constant = new Constantifier(elementMap).visit(node.initializer);
       } else {
-        throw new SpannableAssertionFailure(
+        failedAt(
             field,
             "Unexpected field $field in "
             "KernelWorldBuilder._getConstructorConstant");
       }
     }
     return _constant;
   }
 
   @override
   FieldData copy() {
     return new FieldData(node);
   }
 }