Use entities internally in MemberTypeInformation

pkg/compiler/lib/src/dump_info.dart

 // Copyright (c) 2013, 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 dump_info;
 
 import 'dart:convert'
     show ChunkedConversionSink, JsonEncoder, StringConversionSink;
 
 import 'package:dart2js_info/info.dart';
@@ skipping 108 matching lines @@
     return info;
   }
 
   _resultOfMember(MemberElement e) =>
       compiler.globalInference.results.resultOfMember(e);
 
   _resultOfParameter(ParameterElement e) =>
       compiler.globalInference.results.resultOfParameter(e);
 
   FieldInfo visitFieldElement(FieldElement element, _) {
+    if (!compiler.resolution.hasBeenResolved(element)) return null;

[Johnni Winther, 2017/07/04 13:46:24]

This would trigger a 'type has not been compute' failure on unresolved field,
trying to create the default FieldTypeInformation object.

[Siggi Cherem (dart-lang), 2017/07/05 21:04:14]

do you mean we are hitting this issue on programs with input errors?

[Johnni Winther, 2017/07/06 09:38:14]

No. The visiting just eagerly runs through all fields, regardless of whether
they are live or not.

     TypeMask inferredType = _resultOfMember(element).type;
     // If a field has an empty inferred type it is never used.
     if (inferredType == null || inferredType.isEmpty) return null;
 
     int size = compiler.dumpInfoTask.sizeOf(element);
     String code = compiler.dumpInfoTask.codeOf(element);
     if (code != null) size += code.length;
 
     FieldInfo info = new FieldInfo(
         name: element.name,
@@ skipping 478 matching lines @@
 
     ChunkedConversionSink<Object> sink = encoder.startChunkedConversion(
         new StringConversionSink.fromStringSink(buffer));
     sink.add(new AllInfoJsonCodec().encode(result));
     compiler.reporter.reportInfo(NO_LOCATION_SPANNABLE, MessageKind.GENERIC, {
       'text': "View the dumped .info.json file at "
           "https://dart-lang.github.io/dump-info-visualizer"
     });
   }
 }