Correct the wildcard tests for import prefixes.

An unrelated fix, #3865, revealed that
the wildcard-variables experiment was not actually enabled in tests; the SDK
constraint used in test packages needs to be '^3.6.0'. With that fix, there are
some questions about how much dartdoc should be doing to keep wildcards
"non-binding" and how much the analyzer should be doing. So that is raised in
#3769 (comment).

Author: srawlins

lib/src/model/comment_referable.dart

@@ -7,12 +7,14 @@ library;
 
 import 'dart:core';
 
+import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/scope.dart';
 import 'package:collection/collection.dart';
 import 'package:dartdoc/src/model/library.dart';
 import 'package:dartdoc/src/model/model_element.dart';
 import 'package:dartdoc/src/model/nameable.dart';
+import 'package:dartdoc/src/model/prefix.dart';
 import 'package:meta/meta.dart';
 
 class _ReferenceChildrenLookup {
@@ -55,6 +57,12 @@ mixin CommentReferable implements Nameable {
       // First attempt: Ask analyzer's `Scope.lookup` API.
       var result = _lookupViaScope(referenceLookup, filter: filter);
       if (result != null) {
+        if (result is Prefix &&
+            result.name == '_' &&
+            library!.element.featureSet.isEnabled(Feature.wildcard_variables)) {
+          // A wildcard import prefix is non-binding.
+          continue;
+        }
         return result;
       }
 

lib/src/model/library.dart

@@ -2,6 +2,7 @@
 // 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/analysis/features.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/scope.dart';
 import 'package:analyzer/source/line_info.dart';
@@ -442,6 +443,11 @@ class Library extends ModelElement
     // ambiguous.  dart-lang/dartdoc#2683.
     for (var MapEntry(key: prefix, value: libraries)
         in _prefixToLibrary.entries) {
+      if (prefix == '_' &&
+          element.featureSet.isEnabled(Feature.wildcard_variables)) {
+        // A wildcard import prefix is non-binding.
+        continue;
+      }
       referenceChildrenBuilder.putIfAbsent(prefix, () => libraries.first);
     }
     return referenceChildrenBuilder;

test/dartdoc_test_base.dart

@@ -36,9 +36,12 @@ abstract class DartdocTestBase {
 
   String get linkPrefix => '$placeholder$libraryName';
 
+  String get dartAsyncUrlPrefix =>
+      'https://api.dart.dev/stable/3.2.0/dart-async';
+
   String get dartCoreUrlPrefix => 'https://api.dart.dev/stable/3.2.0/dart-core';
 
-  String get sdkConstraint => '>=3.3.0 <4.0.0';
+  String get sdkConstraint => '>=3.6.0 <4.0.0';
 
   List<String> get experiments => ['wildcard-variables'];
 

test/prefixes_test.dart

@@ -19,6 +19,8 @@ class PrefixesTest extends DartdocTestBase {
   @override
   String get libraryName => 'prefixes';
 
+  @FailingTest(
+      reason: 'requires https://github.com/dart-lang/dartdoc/pull/3865')
   void test_referenced() async {
     var library = await bootPackageWithLibrary(
       '''
@@ -29,9 +31,11 @@ int x = 0;
 ''',
       additionalArguments: ['--link-to-remote'],
     );
-    var f = library.properties.named('x');
-    // There is no link, but also no wrong link or crash.
-    expect(f.documentationAsHtml, '<p>Text <code>async</code>.</p>');
+    var x = library.properties.named('x');
+    expect(
+      x.documentationAsHtml,
+      '<p>Text <a href="$dartAsyncUrlPrefix/dart-async-library.html">async</a>.</p>',
+    );
   }
 
   void test_referenced_wildcard() async {
@@ -44,8 +48,8 @@ int x = 0;
 ''',
       additionalArguments: ['--link-to-remote'],
     );
-    var f = library.properties.named('x');
+    var x = library.properties.named('x');
     // There is no link, but also no wrong link or crash.
-    expect(f.documentationAsHtml, '<p>Text <code>_</code>.</p>');
+    expect(x.documentationAsHtml, '<p>Text <code>_</code>.</p>');
   }
 }