Improve type inference for plugin manager implementations

psalm-baseline.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<files psalm-version="4.22.0@fc2c6ab4d5fa5d644d8617089f012f3bb84b8703">
+<files psalm-version="4.23.0@f1fe6ff483bf325c803df9f510d09a03fd796f88">
   <file src="src/AbstractFactory/ConfigAbstractFactory.php">
     <InvalidStringClass occurrences="1">
       <code>new $requestedName(...$arguments)</code>
@@ -405,7 +405,7 @@
       <code>$names[$name]</code>
       <code>$object[$shared ? $method : 'build']</code>
     </MixedArrayOffset>
-    <MixedAssignment occurrences="26">
+    <MixedAssignment occurrences="24">
       <code>$callSequence</code>
       <code>$first</code>
       <code>$idx1</code>
@@ -502,9 +502,6 @@
     <MissingClosureParamType occurrences="1">
       <code>$autoload</code>
     </MissingClosureParamType>
-    <MixedAssignment occurrences="1">
-      <code>$instance</code>
-    </MixedAssignment>
     <RedundantConditionGivenDocblockType occurrences="2">
       <code>assertIsArray</code>
       <code>assertIsArray</code>

src/AbstractPluginManager.php

@@ -32,6 +32,8 @@
  * The implementation extends `ServiceManager`, thus providing the same set
  * of capabilities as found in that implementation.
  *
+ * @template InstanceType of object
+ * @implements PluginManagerInterface<InstanceType>
  * @psalm-import-type ServiceManagerConfiguration from ServiceManager
  * @psalm-suppress PropertyNotSetInConstructor
  */
@@ -48,7 +50,7 @@ abstract class AbstractPluginManager extends ServiceManager implements PluginMan
      * An object type that the created instance must be instanced of
      *
      * @var null|string
-     * @psalm-var null|class-string
+     * @psalm-var null|class-string<InstanceType>
      */
     protected $instanceOf;
 
@@ -131,6 +133,10 @@ public function configure(array $config)
      * Override setService for additional plugin validation.
      *
      * {@inheritDoc}
+     *
+     * @param string|class-string<InstanceType> $name
+     * @param InstanceType $service
+     * @psalm-suppress MoreSpecificImplementedParamType
      */
     public function setService($name, $service)
     {
@@ -139,9 +145,10 @@ public function setService($name, $service)
     }
 
     /**
-     * @param string $name Service name of plugin to retrieve.
+     * @param class-string<InstanceType>|string $name Service name of plugin to retrieve.
      * @param null|array<mixed> $options Options to use when creating the instance.
      * @return mixed
+     * @psalm-return ($name is class-string ? InstanceType : mixed)
      * @throws Exception\ServiceNotFoundException If the manager does not have
      *     a service definition for the instance, and the service is not
      *     auto-invokable.
@@ -162,14 +169,15 @@ public function get($name, ?array $options = null)
             $this->setFactory($name, Factory\InvokableFactory::class);
         }
 
-        /** @psalm-suppress MixedAssignment */
         $instance = ! $options ? parent::get($name) : $this->build($name, $options);
         $this->validate($instance);
         return $instance;
     }
 
     /**
      * {@inheritDoc}
+     *
+     * @psalm-assert InstanceType $instance
      */
     public function validate($instance)
     {

src/PluginManagerInterface.php

@@ -11,6 +11,8 @@
  * Interface for a plugin manager
  *
  * A plugin manager is a specialized service locator used to create homogeneous objects
+ *
+ * @template InstanceType of object
  */
 interface PluginManagerInterface extends ServiceLocatorInterface
 {
@@ -22,6 +24,7 @@ interface PluginManagerInterface extends ServiceLocatorInterface
      * @throws InvalidServiceException If created instance does not respect the
      *     constraint on type imposed by the plugin manager.
      * @throws ContainerExceptionInterface If any other error occurs.
+     * @psalm-assert InstanceType $instance
      */
     public function validate($instance);
 }

src/ServiceLocatorInterface.php

@@ -15,9 +15,11 @@ interface ServiceLocatorInterface extends ContainerInterface
     /**
      * Build a service by its name, using optional options (such services are NEVER cached).
      *
-     * @param  string $name
+     * @template T of object
+     * @param  string|class-string<T> $name
      * @param  null|array<mixed>  $options
      * @return mixed
+     * @psalm-return ($name is class-string ? T : mixed)
      * @throws Exception\ServiceNotFoundException If no factory/abstract
      *     factory could be found to create the instance.
      * @throws Exception\ServiceNotCreatedException If factory/delegator fails

src/ServiceManager.php

@@ -259,6 +259,9 @@ public function build($name, ?array $options = null)
 
     /**
      * {@inheritDoc}
+     *
+     * @param string|class-string $name
+     * @return bool
      */
     public function has($name)
     {