Add hint for use of ?. in conditions (issue 24649)

pkg/analyzer/test/generated/resolver_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library engine.resolver_test;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/context.dart' as newContext;
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 3135 matching lines @@
   void test_missingReturn_method() {
     Source source = addSource(r'''
 class A {
   int m() {}
 }''');
     computeLibrarySourceErrors(source);
     assertErrors(source, [HintCode.MISSING_RETURN]);
     verify([source]);
   }
 
+  void test_nullAwareInCondition_do() {
+    Source source = addSource(r'''
+m(x) {
+  do {} while (x?.y);
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.NULL_AWARE_IN_CONDITION]);
+    verify([source]);
+  }
+
+  void test_nullAwareInCondition_for() {
+    Source source = addSource(r'''
+m(x) {
+  for (var v = x; v?.y; v = v.next) {}
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.NULL_AWARE_IN_CONDITION]);
+    verify([source]);
+  }
+
+  void test_nullAwareInCondition_if() {
+    Source source = addSource(r'''
+m(x) {
+  if (x?.y) {}
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.NULL_AWARE_IN_CONDITION]);
+    verify([source]);
+  }
+
+  void test_nullAwareInCondition_if_parenthesized() {
+    Source source = addSource(r'''
+m(x) {
+  if ((x?.y)) {}
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.NULL_AWARE_IN_CONDITION]);
+    verify([source]);
+  }
+
+  void test_nullAwareInCondition_while() {
+    Source source = addSource(r'''
+m(x) {
+  while (x?.y) {}
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.NULL_AWARE_IN_CONDITION]);
+    verify([source]);
+  }
+
   void test_overrideOnNonOverridingGetter_invalid() {
     Source source = addSource(r'''
 library dart.core;
 const override = null;
 class A {
 }
 class B extends A {
   @override
   int get m => 1;
 }''');
@@ skipping 3727 matching lines @@
     verify([source]);
   }
 
   void test_missingReturn_voidReturnType() {
     Source source = addSource("void f() {}");
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
     verify([source]);
   }
 
+  void test_nullAwareInCondition_for_noCondition() {
+    Source source = addSource(r'''
+m(x) {
+  for (var v = x; ; v++) {}
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
+  void test_nullAwareInCondition_if_notTopLevel() {
+    Source source = addSource(r'''
+m(x) {
+  if (x?.y == null) {}
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
   void test_overrideEqualsButNotHashCode() {
     Source source = addSource(r'''
 class A {
   bool operator ==(x) { return x; }
   get hashCode => 0;
 }''');
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
     verify([source]);
   }
@@ skipping 7940 matching lines @@
 
   void _resolveTestUnit(String code) {
     testCode = code;
     testSource = addSource(testCode);
     LibraryElement library = resolve2(testSource);
     assertNoErrors(testSource);
     verify([testSource]);
     testUnit = resolveCompilationUnit(testSource, library);
   }
 }