Ensure locations are always provided, but don't store them yet.

pkg/front_end/lib/src/fasta/kernel/kernel_target.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.
 
 library fasta.kernel_target;
 
 import 'dart:async' show
     Future;
 
 import 'dart:io' show
@@ skipping 177 matching lines @@
       }
     });
     return result;
   }
 
   void breakCycle(ClassBuilder builder) {
     Class cls = builder.target;
     cls.implementedTypes.clear();
     cls.supertype = null;
     cls.mixedInType = null;
-    builder.supertype = new KernelNamedTypeBuilder("Object", null)
+    builder.supertype =
+        new KernelNamedTypeBuilder(
+            "Object", null, builder.charOffset,
+            builder.fileUri ?? Uri.parse(cls.fileUri))
         ..builder = objectClassBuilder;
     builder.interfaces = null;
   }
 
   Future<Program> handleInputError(Uri uri, InputError error,
       {bool isFullProgram}) {
     if (error != null) {
       String message = error.format();
       print(message);
       errors.add(message);
@@ skipping 61 matching lines @@
     Uri fileUri = loader.first?.fileUri ?? uri;
     KernelLibraryBuilder library =
         new KernelLibraryBuilder(uri, fileUri, loader);
     loader.first = library;
     if (isFullProgram) {
       // If this is an outline, we shouldn't add an executable main
       // method. Similarly considerations apply to separate compilation. It
       // could also make sense to add a way to mark .dill files as having
       // compile-time errors.
       KernelProcedureBuilder mainBuilder = new KernelProcedureBuilder(null, 0,
-          null, "main", null, null, AsyncMarker.Sync, ProcedureKind.Method);
+          null, "main", null, null, AsyncMarker.Sync, ProcedureKind.Method,
+          library, -1);
       library.addBuilder(mainBuilder.name, mainBuilder);
       mainBuilder.body = new ExpressionStatement(
           new Throw(new StringLiteral("${errors.join('\n')}")));
     }
     library.build();
     return link(<Library>[library.library]);
   }
 
   /// Creates a program by combining [libraries] with the libraries of
   /// `dillTarget.loader.program`.
@@ skipping 296 matching lines @@
     superclass = superclass.superclass;
   }
   for (Constructor constructor in superclass.constructors) {
     if (constructor.name.name.isEmpty) {
       return constructor.function.requiredParameterCount == 0 ?
           constructor : null;
     }
   }
   return null;
 }