Fix a bug in the convert_to_null_aware assist/fix

Bug: #44173
Change-Id: I3b09732fe79577fc394b41a18d58fa8627be5eae
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/171703
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: bwilkerson

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

@@ -86,7 +86,7 @@ class ConvertToNullAware extends CorrectionProducer {
       } else {
         return;
       }
-      if (operator.type != TokenType.PERIOD) {
+      if (operator == null || operator.type != TokenType.PERIOD) {
         return;
       }
       if (!(target is SimpleIdentifier &&

pkg/analysis_server/test/src/services/correction/assist/convert_to_null_aware_test.dart

@@ -11,12 +11,12 @@ import 'assist_processor.dart';
 
 void main() {
   defineReflectiveSuite(() {
-    defineReflectiveTests(ConvertToNormalParameterTest);
+    defineReflectiveTests(ConvertToNullAwareTest);
   });
 }
 
 @reflectiveTest
-class ConvertToNormalParameterTest extends AssistProcessorTest {
+class ConvertToNullAwareTest extends AssistProcessorTest {
   @override
   AssistKind get kind => DartAssistKind.CONVERT_TO_NULL_AWARE;
 
@@ -138,6 +138,18 @@ int f(A a) => a?.p;
 ''');
   }
 
+  Future<void> test_notEqual_noTarget() async {
+    // https://github.com/dart-lang/sdk/issues/44173
+    verifyNoTestUnitErrors = false;
+    await resolveTestCode('''
+foo() {
+  var range = 1;
+  var rangeStart = range != null ? toOffset() : null;
+}
+''');
+    await assertNoAssistAt(' null;');
+  }
+
   Future<void> test_notEqual_notNullPreserving() async {
     await resolveTestCode('''
 abstract class A {