Raise psalm level to the max

Author: jeckel

phpstan.neon

@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <psalm
-    totallyTyped="false"
+    errorLevel="1"
     resolveFromConfigFile="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"
@@ -12,44 +12,4 @@
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
-
-    <issueHandlers>
-        <LessSpecificReturnType errorLevel="info" />
-
-        <!-- level 3 issues - slightly lazy code writing, but provably low false-negatives -->
-
-        <DeprecatedMethod errorLevel="info" />
-        <DeprecatedProperty errorLevel="info" />
-        <DeprecatedClass errorLevel="info" />
-        <DeprecatedConstant errorLevel="info" />
-        <DeprecatedFunction errorLevel="info" />
-        <DeprecatedInterface errorLevel="info" />
-        <DeprecatedTrait errorLevel="info" />
-
-        <InternalMethod errorLevel="info" />
-        <InternalProperty errorLevel="info" />
-        <InternalClass errorLevel="info" />
-
-        <MissingClosureReturnType errorLevel="info" />
-        <MissingReturnType errorLevel="info" />
-        <MissingPropertyType errorLevel="info" />
-        <InvalidDocblock errorLevel="info" />
-        <MisplacedRequiredParam errorLevel="info" />
-
-        <PropertyNotSetInConstructor errorLevel="info" />
-        <MissingConstructor errorLevel="info" />
-        <MissingClosureParamType errorLevel="info" />
-        <MissingParamType errorLevel="info" />
-
-        <RedundantCondition errorLevel="info" />
-
-        <DocblockTypeContradiction errorLevel="info" />
-        <RedundantConditionGivenDocblockType errorLevel="info" />
-
-        <UnresolvableInclude errorLevel="info" />
-
-        <RawObjectIteration errorLevel="info" />
-
-        <InvalidStringClass errorLevel="info" />
-    </issueHandlers>
 </psalm>

psalm.xml

@@ -12,6 +12,7 @@
 /**
  * Trait CommandResponseEventsTrait
  * @package JeckelLab\CommandDispatcher\CommandResponse
+ * @psalm-immutable
  */
 trait CommandResponseEventsTrait
 {

src/CommandResponse/CommandResponseEventsTrait.php

@@ -50,7 +50,9 @@ public function resolve(Command $command): CommandHandler
         }
 
         if ($this->container !== null && $this->container->has($handler)) {
-            return $this->container->get($handler);
+            $instance = $this->container->get($handler);
+            assert($instance instanceof CommandHandler, 'Handler should be an instance of CommandHandler');
+            return $instance;
         }
 
         throw new HandlerNotFoundException(sprintf(