Don't use LinkedEditGroup.id.

pkg/analysis_server/lib/src/services/correction/assist_internal.dart

Index: pkg/analysis_server/lib/src/services/correction/assist_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
index dfa6798387ce95265338835b42d9609a470c6a94..03a473054938e234dfd8c45c498db0ca1e4b0919 100644
--- a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
@@ -1484,7 +1484,7 @@ class AssistProcessor {
   LinkedEditGroup _getLinkedPosition(String groupId) {
     LinkedEditGroup group = linkedPositionGroups[groupId];
     if (group == null) {
-      group = new LinkedEditGroup(groupId);
+      group = new LinkedEditGroup();
       linkedPositionGroups[groupId] = group;
     }
     return group;
@@ -1511,8 +1511,8 @@ class AssistProcessor {
     String text = builder.toString();
     _addInsertEdit(builder.offset, text);
     // add linked positions
-    builder.linkedPositionGroups.forEach((LinkedEditGroup group) {
-      LinkedEditGroup fixGroup = _getLinkedPosition(group.id);
+    builder.linkedPositionGroups.forEach((String id, LinkedEditGroup group) {
+      LinkedEditGroup fixGroup = _getLinkedPosition(id);
       group.positions.forEach((Position position) {
         fixGroup.addPosition(position, group.length);
       });