Apply psalm-inheritors to interfaces too

src/Psalm/Internal/Analyzer/InterfaceAnalyzer.php

@@ -11,9 +11,13 @@ use Psalm\FileManipulation;
 use Psalm\Internal\Analyzer\Statements\Expression\ClassConstAnalyzer;
 use Psalm\Internal\FileManipulation\FileManipulationBuffer;
 use Psalm\Internal\Provider\NodeDataProvider;
+use Psalm\Internal\Type\Comparator\UnionTypeComparator;
+use Psalm\Issue\InheritorViolation;
 use Psalm\Issue\ParseError;
 use Psalm\Issue\UndefinedInterface;
 use Psalm\IssueBuffer;
+use Psalm\Type\Atomic\TNamedObject;
+use Psalm\Type\Union;
 use UnexpectedValueException;
 
 use function strtolower;
@@ -109,6 +113,23 @@ class InterfaceAnalyzer extends ClassLikeAnalyzer
             }
         }
 
+        $class_union = new Union([new TNamedObject($fq_interface_name)]);
+        foreach ($class_storage->direct_interface_parents as $parent_interface) {
+            $parent_storage = $codebase->classlikes->getStorageFor($parent_interface);
+            if ($parent_storage && $parent_storage->inheritors) {
+                if (!UnionTypeComparator::isContainedBy($codebase, $class_union, $parent_storage->inheritors)) {
+                    IssueBuffer::maybeAdd(
+                        new InheritorViolation(
+                            'Interface ' . $fq_interface_name . '
+                             is not an allowed inheritor of parent interface ' . $parent_interface,
+                            new CodeLocation($this, $this->class),
+                        ),
+                        $this->getSuppressedIssues(),
+                    );
+                }
+            }
+        }
+
         $fq_interface_name = $this->getFQCLN();
 
         if (!$fq_interface_name) {

tests/ClassTest.php

@@ -857,7 +857,6 @@ class ClassTest extends TestCase
                      */
                     class BaseClass {}
                     class FooClass extends BaseClass {}
-                    $a = new FooClass();
                     PHP,
             ],
             'unionInheritorIsAllowed' => [
@@ -868,9 +867,7 @@ class ClassTest extends TestCase
                      */
                     class BaseClass {}
                     class FooClass extends BaseClass {}
-                    $a = new FooClass();
                     class BarClass extends FooClass {}
-                    $b = new BarClass();
                     PHP,
             ],
             'multiInheritorIsAllowed' => [
@@ -881,9 +878,7 @@ class ClassTest extends TestCase
                      */
                     class BaseClass {}
                     class FooClass extends BaseClass {}
-                    $a = new FooClass();
                     class BarClass extends FooClass {}
-                    $b = new BarClass();
                     PHP,
             ],
             'skippedInheritorIsAllowed' => [
@@ -894,9 +889,7 @@ class ClassTest extends TestCase
                      */
                     class BaseClass {}
                     class FooClass extends BaseClass {}
-                    $a = new FooClass();
                     class BarClass extends FooClass {}
-                    $b = new BarClass();
                     PHP,
             ],
             'CompositeInheritorIsAllowed' => [
@@ -908,7 +901,6 @@ class ClassTest extends TestCase
                     class BaseClass {}
                     interface FooInterface {}
                     class BarClass extends BaseClass implements FooInterface {}
-                    $b = new BarClass();
                     PHP,
             ],
             'InterfaceInheritorIsAllowed' => [
@@ -919,9 +911,7 @@ class ClassTest extends TestCase
                      */
                     interface BaseInterface {}
                     class FooClass implements BaseInterface {}
-                    $a = new FooClass();
                     class BarClass implements BaseInterface {}
-                    $b = new BarClass();
                     PHP,
             ],
             'MultiInterfaceInheritorIsAllowed' => [
@@ -936,7 +926,16 @@ class ClassTest extends TestCase
                      */
                     interface InterfaceB {}
                     class FooClass implements InterfaceA, InterfaceB {}
-                    $a = new FooClass();
+                    PHP,
+                ],
+            'InterfaceOfInterfaceInheritorIsAllowed' => [
+                        'code' => <<<'PHP'
+                    <?php
+                    /**
+                     * @psalm-inheritors InterfaceB
+                     */
+                    interface InterfaceA {}
+                    interface InterfaceB extends InterfaceA {}
                     PHP,
             ],
         ];
@@ -1409,6 +1408,18 @@ class ClassTest extends TestCase
                 'error_message' => 'InheritorViolation',
                 'ignored_issues' => [],
             ],
+            'interfaceCannotImplementIfNotInInheritors' => [
+                'code' => <<<'PHP'
+                    <?php
+                    /**
+                     * @psalm-inheritors FooClass|BarClass
+                     */
+                    interface BaseInterface {}
+                    interface BazInterface extends BaseInterface {}
+                    PHP,
+                'error_message' => 'InheritorViolation',
+                'ignored_issues' => [],
+            ],
             'UnfulfilledInterfaceInheritors' => [
                 'code' => <<<'PHP'
                     <?php