handle library_private_types_in_public_api false positives for modified classes (#4534)

Author: pq

lib/src/rules/library_private_types_in_public_api.dart

@@ -94,9 +94,20 @@ class Validator extends SimpleAstVisitor<void> {
     if (name != null && Identifier.isPrivateName(name.lexeme)) {
       return;
     }
+
     // Enum constructors are effectively private so don't visit their params.
     if (node.parent is EnumDeclaration) return;
 
+    // Select modified class types are also effectively private.
+    var enclosingElement = node.declaredElement?.enclosingElement;
+    if (enclosingElement is ClassElement) {
+      if (enclosingElement.isSealed) return;
+      if (enclosingElement.isAbstract) {
+        if (enclosingElement.isInterface) return;
+        if (enclosingElement.isFinal) return;
+      }
+    }
+
     node.parameters.accept(this);
   }
 

test/rules/library_private_types_in_public_api_test.dart

@@ -18,6 +18,30 @@ class LibraryPrivateTypesInPublicApiEnumTest extends LintRuleTest {
   @override
   String get lintRule => 'library_private_types_in_public_api';
 
+  test_abstractFinal_constructorParams() async {
+    await assertNoDiagnostics(r'''
+class _O {
+  const _O();
+}
+
+abstract final class E {
+  E(_O o);
+}
+''');
+  }
+
+  test_abstractInterface_constructorParams() async {
+    await assertNoDiagnostics(r'''
+class _O {
+  const _O();
+}
+
+abstract interface class E {
+  E(_O o);
+}
+''');
+  }
+
   test_enum() async {
     await assertDiagnostics(r'''
 class _O {}
@@ -44,6 +68,18 @@ enum E {
   a(_O());
   const E(_O o);
 }
+''');
+  }
+
+  test_sealed_constructorParams() async {
+    await assertNoDiagnostics(r'''
+class _O {
+  const _O();
+}
+
+sealed class E {
+  E(_O o);
+}
 ''');
   }
 }