Limit template annotations to Psalm

Phpstan requires that the template can be resolved in all cases, while
Psalm seems to tolerate this ambiguous situation.
See phpstan/phpstan#5175 (comment)

lib/Doctrine/ORM/EntityManagerInterface.php

@@ -321,11 +321,13 @@ public function hasFilters();
      * {@inheritDoc}
      *
      * @psalm-param string|class-string<T> $className
+     * @phpstan-param string $className
      *
      * @return Mapping\ClassMetadata
      * @psalm-return Mapping\ClassMetadata<T>
+     * @phpstan-return Mapping\ClassMetadata<object>
      *
-     * @template T of object
+     * @psalm-template T of object
      */
     public function getClassMetadata($className);
 }

tests/Doctrine/StaticAnalysis/get-metadata.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Doctrine\StaticAnalysis;
+
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\Mapping\ClassMetadata;
+
+/**
+ * EntityManagerInterface::getClassMetadata() is templated only for Psalm,
+ * because of limitations in PHPStan.
+ *
+ * @see https://github.com/phpstan/phpstan/issues/5175#issuecomment-861437050
+ */
+abstract class GetMetadata
+{
+    /**
+     * @param string|object $class
+     * @phpstan-param class-string|object $class
+     */
+    abstract public function getEntityManager($class): EntityManagerInterface;
+
+    /**
+     * @psalm-param class-string<TObject> $class
+     * @phpstan-param class-string $class
+     *
+     * @psalm-return ClassMetadata<TObject>
+     * @phpstan-return ClassMetadata<object>
+     *
+     * @psalm-template TObject of object
+     */
+    public function __invoke(string $class): ClassMetadata
+    {
+        return $this->getEntityManager($class)->getClassMetadata($class);
+    }
+}