Use withNullability(true) in ElementImpl.toString().

Change-Id: Ie7896e564ab5b86c6398d5d70352301319b99535
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/159940
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
diff --git a/pkg/analyzer/CHANGELOG.md b/pkg/analyzer/CHANGELOG.md
index 7ff78e1..1eb1e16 100644
--- a/pkg/analyzer/CHANGELOG.md
+++ b/pkg/analyzer/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 0.40.1-dev
 * Added `LocalVariableElement.hasInitializer`,
   `PropertyInducingElement.hasInitializer`, `ParameterElement.hasDefaultValue`.
+* `ElementImpl.toString()` uses `getDisplayString(withNullability: true)`.
 
 ## 0.40.0
 * Added `LibraryElement.featureSet`.
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index 3df5109..9115009 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -3112,7 +3112,7 @@
 
   @override
   String toString() {
-    return getDisplayString(withNullability: false);
+    return getDisplayString(withNullability: true);
   }
 
   @override