[PE] [linter] make strict_top_level_inference reflectiveTest aware

Turning on this lint in the linter in anticipation of a `package:lints` roll flagged 5K+ violations for test methods missing return types. Since these methods can only be called by the framework, the added type information is of negligible value and just adds noise.


Change-Id: I9b7d0c12d51fb512c0f68e09233cec841ed372df
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/412361
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

pkg/linter/lib/src/rules/strict_top_level_inference.dart

@@ -212,7 +212,9 @@ class _Visitor extends SimpleAstVisitor<void> {
       var overriddenMember = context.inheritanceManager.overriddenMember(
         node.declaredFragment?.element,
       );
-      if (overriddenMember == null && node.returnType == null) {
+      if (overriddenMember == null &&
+          node.returnType == null &&
+          !container.isReflectiveTest) {
         _report(node.name);
       }
       if (node.parameters case var parameters?) {
@@ -264,3 +266,23 @@ class _Visitor extends SimpleAstVisitor<void> {
     }
   }
 }
+
+extension on InstanceElement2 {
+  // TODO(pq): share w/ unreachable_from_main
+  bool get isReflectiveTest {
+    var self = this;
+    if (self is! ClassElement2) return false;
+
+    var metadata = self.metadata2;
+    for (var i = 0; i < metadata.annotations.length; i++) {
+      var annotation = metadata.annotations[i].element2;
+      if (annotation is GetterElement &&
+          annotation.name3 == 'reflectiveTest' &&
+          annotation.library2.uri.toString() ==
+              'package:test_reflective_loader/test_reflective_loader.dart') {
+        return true;
+      }
+    }
+    return false;
+  }
+}

pkg/linter/test/rules/strict_top_level_inference_test.dart

@@ -683,6 +683,33 @@ void f() {
 ''');
   }
 
+  test_reflectiveTest() async {
+    // TODO(pq): share setup logic with unreachable_from_main_test
+    var testReflectiveLoaderPath = '$workspaceRootPath/test_reflective_loader';
+    var packageConfigBuilder = PackageConfigFileBuilder();
+    packageConfigBuilder.add(
+      name: 'test_reflective_loader',
+      rootPath: testReflectiveLoaderPath,
+    );
+    writeTestPackageConfig(packageConfigBuilder);
+    newFile('$testReflectiveLoaderPath/lib/test_reflective_loader.dart', r'''
+library test_reflective_loader;
+
+const Object reflectiveTest = _ReflectiveTest();
+class _ReflectiveTest {
+  const _ReflectiveTest();
+}
+''');
+    await assertNoDiagnostics(r'''
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+@reflectiveTest
+class ReflectiveTest {
+  test_foo() {}
+}
+''');
+  }
+
   test_staticField_final() async {
     await assertNoDiagnostics(r'''
 class C {