diff --git a/core/.phpstan-baseline.php b/core/.phpstan-baseline.php
index 789b1e63b598f731f3e8f64f965858785e6d10e1..e6850a6c6656ded14faccef52f9932a3085aa319 100644
--- a/core/.phpstan-baseline.php
+++ b/core/.phpstan-baseline.php
@@ -1131,6 +1131,16 @@
 	'count' => 1,
 	'path' => __DIR__ . '/modules/migrate/src/Plugin/migrate/destination/NullDestination.php',
 ];
+$ignoreErrors[] = [
+  'message' => '#^@dataProvider providerSource related method not found\\.$#',
+  'count' => 1,
+  'path' => __DIR__ . '/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php',
+];
+$ignoreErrors[] = [
+  'message' => '#^@dataProvider providerSource related method not found\\.$#',
+  'count' => 1,
+  'path' => __DIR__ . '/modules/migrate/tests/src/Kernel/MigrateSqlSourceTestBase.php',
+];
 $ignoreErrors[] = [
 	'message' => '#^Call to an undefined static method Drupal\\\\Tests\\\\migrate\\\\Kernel\\\\MigrateTestBase\\:\\:migrateDumpAlter\\(\\)\\.$#',
 	'count' => 1,
diff --git a/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php b/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php
index f102b4b411266564e2939d424c08a728ce51f7bb..ba3317ba2aaa1c5284a72f1901da71ca9b60c292 100644
--- a/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php
+++ b/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php
@@ -9,6 +9,29 @@
 
 /**
  * Base class for tests of Migrate source plugins.
+ *
+ * Implementing classes must declare a providerSource() method for this class
+ * to work, defined as follows:
+ *
+ * @code
+ * abstract public static function providerSource(): array;
+ * @endcode
+ *
+ * The returned array should be as follows:
+ *
+ * @code
+ *    Array of data sets to test, each of which is a numerically indexed array
+ *    with the following elements:
+ *    - An array of source data, which can be optionally processed and set up
+ *      by subclasses.
+ *    - An array of expected result rows.
+ *    - (optional) The number of result rows the plugin under test is expected
+ *      to return. If this is not a numeric value, the plugin will not be
+ *      counted.
+ *    - (optional) Array of configuration options for the plugin under test.
+ * @endcode
+ *
+ * @see \Drupal\Tests\migrate\Kernel\MigrateSourceTestBase::testSource
  */
 abstract class MigrateSourceTestBase extends KernelTestBase {
 
@@ -31,24 +54,6 @@ abstract class MigrateSourceTestBase extends KernelTestBase {
    */
   protected $plugin;
 
-  /**
-   * The data provider.
-   *
-   * @see \Drupal\Tests\migrate\Kernel\MigrateSourceTestBase::testSource
-   *
-   * @return array
-   *   Array of data sets to test, each of which is a numerically indexed array
-   *   with the following elements:
-   *   - An array of source data, which can be optionally processed and set up
-   *     by subclasses.
-   *   - An array of expected result rows.
-   *   - (optional) The number of result rows the plugin under test is expected
-   *     to return. If this is not a numeric value, the plugin will not be
-   *     counted.
-   *   - (optional) Array of configuration options for the plugin under test.
-   */
-  abstract public static function providerSource();
-
   /**
    * {@inheritdoc}
    */