Handle variable declarations in inferrer

tests/compiler/dart2js/equivalence/id_equivalence_helper.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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/common_elements.dart';
 import 'package:compiler/src/compiler.dart';
@@ skipping 112 matching lines @@
       annotations
           .putIfAbsent(data.sourceSpan.begin, () => [])
           .add('${data.value}');
     });
     return withAnnotations(annotations);
   }
 
   String get diffCode {
     Map<int, List<String>> annotations = <int, List<String>>{};
     actualMap.forEach((Id id, ActualData data) {
-      String expected = expectedMap[id]?.value ?? '';
-      if (data.value != expected) {
+      IdValue value = expectedMap[id];
+      if (data.value != value || value == null && data.value.value != '') {
+        String expected = value?.toString() ?? '';
         annotations
             .putIfAbsent(data.sourceSpan.begin, () => [])
             .add('${expected} | ${data.value}');
       }
     });
     expectedMap.forEach((Id id, IdValue expected) {
       if (!actualMap.containsKey(id)) {
         int offset = compiler.reporter
             .spanFromSpannable(
                 computeSpannable(elementEnvironment, mainUri, id))
@@ skipping 104 matching lines @@
   Set<Id> missingIds = new Set<Id>();
   data.expectedMap.forEach((Id id, IdValue expected) {
     if (!data.actualMap.containsKey(id)) {
       missingIds.add(id);
       reportHere(
           data.compiler.reporter,
           computeSpannable(data.elementEnvironment, data.mainUri, id),
           'Expected $expected for id $id missing in ${data.actualMap.keys}');
     }
   });
+  if (missingIds.isNotEmpty) {
+    print('--annotations diff--------------------------------------------');
+    print(data.diffCode);
+    print('--------------------------------------------------------------');
+  }
   Expect.isTrue(missingIds.isEmpty, "Ids not found: ${missingIds}.");
 }
 
 /// Compute a [Spannable] from an [id] in the library [mainUri].
 Spannable computeSpannable(
     ElementEnvironment elementEnvironment, Uri mainUri, Id id) {
   if (id is NodeId) {
     return new SourceSpan(mainUri, id.value, id.value + 1);
   } else if (id is ElementId) {
     LibraryEntity library = elementEnvironment.lookupLibrary(mainUri);
@@ skipping 10 matching lines @@
 
 /// Compute the expectancy map from [code].
 Map<Id, IdValue> computeExpectedMap(AnnotatedCode code) {
   Map<Id, IdValue> map = <Id, IdValue>{};
   for (Annotation annotation in code.annotations) {
     IdValue idValue = IdValue.decode(annotation.offset, annotation.text);
     map[idValue.id] = idValue;
   }
   return map;
 }