Issue 26034#3. Fix for indexing references to synthetic fields.

pkg/analyzer/lib/src/summary/index_unit.dart

Index: pkg/analyzer/lib/src/summary/index_unit.dart
diff --git a/pkg/analyzer/lib/src/summary/index_unit.dart b/pkg/analyzer/lib/src/summary/index_unit.dart
index c8462579b7f056a1cdb5ed4456466b4be15e5f95..b239d5caa2e62ac2cf1e423e36488ba85312b5e1 100644
--- a/pkg/analyzer/lib/src/summary/index_unit.dart
+++ b/pkg/analyzer/lib/src/summary/index_unit.dart
@@ -207,6 +207,11 @@ class PackageIndexAssembler {
       } else if (element is FunctionElement && element.name == 'loadLibrary') {
         kind = IndexSyntheticElementKind.loadLibrary;
         element = element.library;
+      } else if (element is FieldElement) {
+        FieldElement field = element;
+        kind = IndexSyntheticElementKind.field;
+        element = field.getter;
+        element ??= field.setter;
       } else if (element is PropertyAccessorElement) {
         PropertyAccessorElement accessor = element;
         Element enclosing = element.enclosingElement;