fix public_member_api_docs overreporting on uninstantiable constructors

Author: pq

lib/src/rules/public_member_api_docs.dart

@@ -226,11 +226,21 @@ class _Visitor extends SimpleAstVisitor {
 
   @override
   void visitConstructorDeclaration(ConstructorDeclaration node) {
-    if (!inPrivateMember(node) &&
-        !isPrivate(node.name) &&
-        node.parent is! EnumDeclaration) {
-      check(node);
+    if (inPrivateMember(node) || isPrivate(node.name)) return;
+    var parent = node.parent;
+    if (parent is EnumDeclaration) return;
+    if (parent is ClassDeclaration) {
+      var classElement = parent.declaredElement;
+      if (classElement != null) {
+        if (classElement.isSealed) return;
+        if (classElement.isAbstract) {
+          if (classElement.isFinal) return;
+          if (classElement.isInterface) return;
+        }
+      }
     }
+
+    check(node);
   }
 
   @override

test/rules/public_member_api_docs_test.dart

@@ -17,6 +17,50 @@ class PublicMemberApiDocsTest extends LintRuleTest {
   @override
   String get lintRule => 'public_member_api_docs';
 
+  /// https://github.com/dart-lang/linter/issues/4526
+  test_abstractFinalConstructor() async {
+    await assertDiagnostics(r'''
+abstract final class S {
+  S();
+}
+
+final class A extends S {}
+''', [
+      lint(21, 1),
+      // No lint on `S()` declaration
+      lint(47, 1),
+    ]);
+  }
+
+  /// https://github.com/dart-lang/linter/issues/4526
+  test_abstractInterfaceConstructor() async {
+    await assertDiagnostics(r'''
+abstract interface class S {
+  S();
+}
+
+final class A extends S {}
+''', [
+      lint(25, 1),
+      // No lint on `S()` declaration
+      lint(51, 1),
+    ]);
+  }
+
+  test_annotatedEnumValue() async {
+    await assertNoDiagnostics(r'''
+/// Documented.
+enum A {
+  /// This represents 'a'.
+  @Deprecated("Use 'b'")
+  a,
+
+  /// This represents 'b'.
+  b;
+}
+''');
+  }
+
   test_enum() async {
     await assertDiagnostics(r'''
 enum A {
@@ -49,20 +93,6 @@ enum A {
 ''');
   }
 
-  test_annotatedEnumValue() async {
-    await assertNoDiagnostics(r'''
-/// Documented.
-enum A {
-  /// This represents 'a'.
-  @Deprecated("Use 'b'")
-  a,
-
-  /// This represents 'b'.
-  b;
-}
-''');
-  }
-
   /// https://github.com/dart-lang/linter/issues/3525
   test_extension() async {
     await assertDiagnostics(r'''
@@ -93,4 +123,19 @@ mixin M {
   String toString() => '';
 }''');
   }
+
+  /// https://github.com/dart-lang/linter/issues/4526
+  test_sealedConstructor() async {
+    await assertDiagnostics(r'''
+sealed class S {
+  S();
+}
+
+final class A extends S {}
+''', [
+      lint(13, 1),
+      // No lint on `S()` declaration
+      lint(39, 1),
+    ]);
+  }
 }