Write tests and implementation for conditional expression remove_comparison quickfix.

Change-Id: Ifc3373895b8c96e610e9515e0cae92be85e8d0b5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/436161
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

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

@@ -85,6 +85,8 @@ class RemoveComparison extends ResolvedCorrectionProducer {
       await _ifElement(parent, builder);
     } else if (parent is IfStatement) {
       await _ifStatement(parent, builder);
+    } else if (parent is ConditionalExpression) {
+      await _conditionalExpression(parent, builder);
     }
   }
 
@@ -111,6 +113,24 @@ class RemoveComparison extends ResolvedCorrectionProducer {
     return buffer.toString();
   }
 
+  Future<void> _conditionalExpression(
+    ConditionalExpression node,
+    ChangeBuilder builder,
+  ) async {
+    Future<void> replaceWithExpression(Expression expression) async {
+      var text = utils.getNodeText(expression);
+      await builder.addDartFileEdit(file, (builder) {
+        builder.addSimpleReplacement(range.node(node), text);
+      });
+    }
+
+    if (_conditionIsTrue) {
+      await replaceWithExpression(node.thenExpression);
+    } else if (_conditionIsFalse) {
+      await replaceWithExpression(node.elseExpression);
+    }
+  }
+
   Future<void> _ifElement(IfElement node, ChangeBuilder builder) async {
     Future<void> replaceWithElement(CollectionElement element) async {
       var text = _textWithLeadingComments(element);

pkg/analysis_server/test/src/services/correction/fix/remove_comparison_test.dart

@@ -155,6 +155,32 @@ void f(String s) {
 ''');
   }
 
+  Future<void> test_conditional_expression_alwaysFalse() async {
+    await resolveTestCode('''
+void f(int x) {
+  print(x == null ? 1 : 0);
+}
+''');
+    await assertHasFix('''
+void f(int x) {
+  print(0);
+}
+''', errorFilter: _ignoreDeadCode);
+  }
+
+  Future<void> test_conditional_expression_alwaysTrue() async {
+    await resolveTestCode('''
+void f(int x) {
+  print(x != null ? 1 : 0);
+}
+''');
+    await assertHasFix('''
+void f(int x) {
+  print(1);
+}
+''', errorFilter: _ignoreDeadCode);
+  }
+
   Future<void> test_ifElement_alwaysFalse_hasElse() async {
     await resolveTestCode('''
 void f(int x) {
@@ -789,6 +815,32 @@ class RemoveTypeCheckTest extends FixProcessorTest {
   @override
   FixKind get kind => DartFixKind.REMOVE_TYPE_CHECK;
 
+  Future<void> test_conditional_expression_alwaysFalse() async {
+    await resolveTestCode('''
+void f(int x) {
+  print(x is! int ? 1 : 0);
+}
+''');
+    await assertHasFix('''
+void f(int x) {
+  print(0);
+}
+''', errorFilter: _ignoreDeadCode);
+  }
+
+  Future<void> test_conditional_expression_alwaysTrue() async {
+    await resolveTestCode('''
+void f(int x) {
+  print(x is int ? 1 : 0);
+}
+''');
+    await assertHasFix('''
+void f(int x) {
+  print(1);
+}
+''', errorFilter: _ignoreDeadCode);
+  }
+
   Future<void> test_unnecessaryTypeCheck_false() async {
     await resolveTestCode('''
 void f(int a, int b) {