CQ. Index and search '// [diag.fooBar]' inside analyzer tests.

Teach the analysis index and referenced-name computation to recognize
`// [diag.foo]` expectation comments embedded in string literals in
analyzer tests. Resolve `foo` through the analyzer diagnostic library
and record it as a qualified reference to the diagnostic variable.

This lets reference search find diagnostics that are used only in test
expectation strings, when developing analyzer itself.

Change-Id: I91fa020ccd2cfe49fa6e890c8f6796a5b8ca4d1f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/503663
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -109,7 +109,7 @@ testFineAfterLibraryAnalyzerHook;
 // TODO(scheglov): Clean up the list of implicitly analyzed files.
 class AnalysisDriver {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 632;
+  static const int DATA_VERSION = 633;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/dart/analysis/index.dart

@@ -324,7 +324,7 @@ class _IndexAssembler {
 
   /// Index the [unit] and assemble a new [AnalysisDriverUnitIndexBuilder].
   AnalysisDriverUnitIndexBuilder assemble(CompilationUnit unit) {
-    unit.accept(_IndexContributor(this));
+    unit.accept(_IndexContributor(this, unit));
 
     // Sort strings and set IDs.
     List<_StringInfo> stringInfoList = stringMap.values.toList(growable: false);
@@ -506,9 +506,20 @@ class _IndexAssembler {
 
 /// Visits a resolved AST and adds relationships into the [assembler].
 class _IndexContributor extends GeneralizingAstVisitor {
-  final _IndexAssembler assembler;
+  static final _expectationPattern = RegExp(
+    r'//[ \t]*\[diag\.([a-zA-Z0-9_]+)\]',
+  );
 
-  _IndexContributor(this.assembler);
+  final _IndexAssembler assembler;
+  final CompilationUnit unit;
+
+  /// Caches the diagnostic library if the unit being indexed is an analyzer
+  /// test file. This enables synthetic indexing of expectation comments
+  /// embedded in string literals (e.g. `// [diag.foo]`).
+  late final LibraryElementImpl? _analyzerDiagnosticLibrary =
+      _findAnalyzerDiagnosticLibrary();
+
+  _IndexContributor(this.assembler, this.unit);
 
   /// Record that the name [node] has a relation of the given [kind].
   void recordNameRelation(
@@ -1172,6 +1183,32 @@ class _IndexContributor extends GeneralizingAstVisitor {
     recordRelation(element, kind, node, isQualified);
   }
 
+  @override
+  void visitSimpleStringLiteral(SimpleStringLiteral node) {
+    // Index analyzer diagnostic expectations inside string literals.
+    if (_analyzerDiagnosticLibrary case var diagnosticLibrary?) {
+      var lexeme = node.literal.lexeme;
+      var matches = _expectationPattern.allMatches(lexeme);
+      var tokenOffset = node.literal.offset;
+      for (var match in matches) {
+        var name = match.group(1)!;
+        var start = (match.end - 1) - name.length;
+        var element = diagnosticLibrary.exportNamespace.get2(name);
+        if (element is GetterElement) {
+          recordRelationOffset(
+            element.variable,
+            IndexRelationKind.IS_REFERENCED_BY,
+            tokenOffset + start,
+            name.length,
+            true,
+          );
+        }
+      }
+    }
+
+    super.visitSimpleStringLiteral(node);
+  }
+
   @override
   void visitSuperConstructorInvocation(SuperConstructorInvocation node) {
     var element = node.element;
@@ -1317,6 +1354,35 @@ class _IndexContributor extends GeneralizingAstVisitor {
     );
   }
 
+  LibraryElementImpl? _findAnalyzerDiagnosticLibrary() {
+    var unitLibrary = unit.declaredFragment!.element;
+
+    var uriStr = unitLibrary.uri.toString();
+    var isAnalyzerTest =
+        uriStr.startsWith('package:test/') ||
+        uriStr.contains('/pkg/analyzer/test/');
+    if (!isAnalyzerTest) {
+      return null;
+    }
+
+    if (unitLibrary is LibraryElementImpl) {
+      var elementFactory = unitLibrary.session.elementFactory;
+      var diagnosticLibrary = elementFactory.libraryOfUri(
+        Uri.parse('package:analyzer/src/diagnostic/diagnostic.dart'),
+      );
+      if (diagnosticLibrary != null) {
+        return diagnosticLibrary;
+      }
+      diagnosticLibrary = elementFactory.libraryOfUri(
+        Uri.parse('package:test/diagnostic.dart'),
+      );
+      if (diagnosticLibrary != null) {
+        return diagnosticLibrary;
+      }
+    }
+    return null;
+  }
+
   /// If the given [constructor] is a synthetic constructor created for a
   /// [ClassTypeAlias], return the actual constructor of a [ClassDeclaration]
   /// which is invoked.  Return `null` if a redirection cycle is detected.

pkg/analyzer/lib/src/dart/analysis/referenced_names.dart

@@ -212,6 +212,10 @@ class _LocalNameScope {
 }
 
 class _ReferencedNamesComputer extends GeneralizingAstVisitor<void> {
+  static final RegExp _analyzerExpectedDiagnosticPattern = RegExp(
+    r'//[ \t]*\[diag\.([a-zA-Z0-9_]+)\]',
+  );
+
   final Set<String> names = <String>{};
   final Set<String> importPrefixNames = <String>{};
 
@@ -375,6 +379,16 @@ class _ReferencedNamesComputer extends GeneralizingAstVisitor<void> {
     names.add(name);
   }
 
+  @override
+  void visitSimpleStringLiteral(SimpleStringLiteral node) {
+    var lexeme = node.literal.lexeme;
+    var matches = _analyzerExpectedDiagnosticPattern.allMatches(lexeme);
+    for (var match in matches) {
+      names.add(match.group(1)!);
+    }
+    super.visitSimpleStringLiteral(node);
+  }
+
   @override
   void visitSuperFormalParameter(SuperFormalParameter node) {
     names.add(node.name.lexeme);

pkg/analyzer/test/src/dart/analysis/index_test.dart

@@ -62,6 +62,33 @@ class IndexTest extends PubPackageResolutionTest with _IndexMixin {
     expect(actual, expected);
   }
 
+  test_analyzer_diagnosticCode() async {
+    var diagnosticFile = newFile('$testPackageLibPath/diagnostic.dart', r'''
+const myDiagnosticCode = 0;
+''');
+
+    var diagnosticLibrary = await libraryElementForFile(diagnosticFile);
+    var element = diagnosticLibrary.topLevelVariables.firstWhere(
+      (v) => v.name == 'myDiagnosticCode',
+    );
+
+    newFile('$testPackageLibPath/helper.dart', r'''
+import 'diagnostic.dart';
+''');
+
+    await _indexTestUnit(r'''
+import 'helper.dart';
+
+void f() {
+  '// [diag.myDiagnosticCode] message';
+}
+''');
+
+    assertElementIndexText(element, r'''
+46 4:13 |myDiagnosticCode| IS_REFERENCED_BY qualified
+''');
+  }
+
   test_ClassElement_emptyBody() async {
     await _indexTestUnit(r'''
 class C;

pkg/analyzer/test/src/dart/analysis/search_test.dart

@@ -1498,6 +1498,34 @@ class C {
 ''');
   }
 
+  test_searchReferences_analyzer_diagnosticCode() async {
+    var diagnosticFile = newFile('$testPackageLibPath/diagnostic.dart', r'''
+const myDiagnosticCode = 0;
+''');
+
+    var diagnosticLibrary = await libraryElementForFile(diagnosticFile);
+    var element = diagnosticLibrary.topLevelVariables.firstWhere(
+      (v) => v.name == 'myDiagnosticCode',
+    );
+
+    newFile('$testPackageLibPath/helper.dart', r'''
+import 'diagnostic.dart';
+''');
+
+    await resolveTestCode(r'''
+import 'helper.dart';
+
+void f() {
+  '// [diag.myDiagnosticCode]';
+}
+''');
+
+    await assertElementReferencesText(element, r'''
+<testLibraryFragment> f@28
+  46 4:13 |myDiagnosticCode| REFERENCE qualified
+''');
+  }
+
   @SkippedTest() // TODO(scheglov): implement augmentation
   test_searchReferences_class_constructor_declaredInAugmentation() async {
     newFile('$testPackageLibPath/a.dart', r'''