Reapply "[analyzer] Add experimental_member_use warning."

This reverts commit 3bdbced.

This change was originally landed as commit
3923958, however it had to be
reverted due to breaking the dart->flutter roll.

Change-Id: I6a6a6964176a276be1b9b01c74a4500488470219
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/452528
Reviewed-by: Samuel Rawlins <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

pkg/analysis_server_plugin/pubspec.yaml

@@ -11,7 +11,7 @@ resolution: workspace
 dependencies:
   # See the release policy for managing this dependency at
   # pkg/analyzer/doc/implementation/releasing.md.
-  analyzer: 8.3.0
+  analyzer: 8.4.0-dev
   analyzer_plugin: 0.13.9
   meta: ^1.16.0
   yaml: ^3.1.0

pkg/analyzer/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 8.4.0-dev
+* Add the `experimental_member_use` warning, which warns about any reference to
+  a declaration annotated with `@experimental`.
+
 ## 8.3.0
 * Deprecate `TypeDefiningElement`, check for specific elements.
 * Deprecate `TypeDefiningFragment`, check for specific fragments.

pkg/analyzer/lib/src/error/best_practices_verifier.dart

@@ -33,6 +33,7 @@ import 'package:analyzer/src/error/deprecated_member_use_verifier.dart';
 import 'package:analyzer/src/error/doc_comment_verifier.dart';
 import 'package:analyzer/src/error/element_usage_frontier_detector.dart';
 import 'package:analyzer/src/error/error_handler_verifier.dart';
+import 'package:analyzer/src/error/experimental_member_use_verifier.dart';
 import 'package:analyzer/src/error/must_call_super_verifier.dart';
 import 'package:analyzer/src/error/null_safe_api_verifier.dart';
 import 'package:analyzer/src/error/widget_preview_verifier.dart';
@@ -123,6 +124,13 @@ class BestPracticesVerifier extends RecursiveAstVisitor<void> {
              diagnosticReporter: _diagnosticReporter,
            ),
          ),
+         ElementUsageFrontierDetector(
+           workspacePackage: workspacePackage,
+           elementUsageSet: const ExperimentalElementUsageSet(),
+           elementUsageReporter: ExperimentalElementUsageReporter(
+             diagnosticReporter: _diagnosticReporter,
+           ),
+         ),
        ],
        _errorHandlerVerifier = ErrorHandlerVerifier(
          _diagnosticReporter,

pkg/analyzer/lib/src/error/experimental_member_use_verifier.dart

@@ -0,0 +1,45 @@
+// Copyright (c) 2025, 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.
+
+import 'package:analyzer/dart/ast/syntactic_entity.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/error/listener.dart';
+import 'package:analyzer/src/error/codes.dart';
+import 'package:analyzer/src/error/element_usage_detector.dart';
+
+/// Instance of [ElementUsageReporter] for reporting uses of experimental
+/// elements.
+class ExperimentalElementUsageReporter implements ElementUsageReporter<()> {
+  final DiagnosticReporter _diagnosticReporter;
+
+  ExperimentalElementUsageReporter({
+    required DiagnosticReporter diagnosticReporter,
+  }) : _diagnosticReporter = diagnosticReporter;
+
+  @override
+  void report(
+    SyntacticEntity errorEntity,
+    String displayName,
+    () tagInfo, {
+    required bool isInSamePackage,
+  }) {
+    // Use of an experimental API from within the same package is OK
+    if (isInSamePackage) return;
+
+    _diagnosticReporter.atEntity(
+      errorEntity,
+      WarningCode.experimentalMemberUse,
+      arguments: [displayName],
+    );
+  }
+}
+
+/// Instance of [ElementUsageSet] for experimental elements.
+class ExperimentalElementUsageSet implements ElementUsageSet<()> {
+  const ExperimentalElementUsageSet();
+
+  @override
+  ()? getTagInfo(Element element) =>
+      element.metadata.annotations.any((e) => e.isExperimental) ? () : null;
+}

pkg/analyzer/pubspec.yaml

@@ -1,5 +1,5 @@
 name: analyzer
-version: 8.3.0
+version: 8.4.0-dev
 description: >-
   This package provides a library that performs static analysis of Dart code.
 repository: https://github.com/dart-lang/sdk/tree/main/pkg/analyzer