Issue 22316. Don't propose to create invalid local variable.

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

Index: pkg/analysis_server/lib/src/services/correction/fix_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
index dbe4636640de26d28f1a6287cb0888a955c8853d..ff9dd933ed261065750f0e040bb8c51d8079f72a 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
@@ -835,8 +835,13 @@ class FixProcessor {
     SourceBuilder sb = new SourceBuilder(file, target.offset);
     {
       // append type
-      DartType fieldType = _inferUndefinedExpressionType(node);
-      _appendType(sb, fieldType, groupId: 'TYPE', orVar: true);
+      DartType type = _inferUndefinedExpressionType(node);
+      if (!(type == null ||
+          type is InterfaceType ||
+          type is FunctionType && type.element != null && !type.element.isSynthetic)) {
+        return;
+      }
+      _appendType(sb, type, groupId: 'TYPE', orVar: true);
       // append name
       {
         sb.startPosition('NAME');