Fix hasSideEffects for AnnotationMethodReflection

src/Reflection/Annotations/AnnotationMethodReflection.php

@@ -109,6 +109,10 @@ public function getThrowType(): ?Type
 
 	public function hasSideEffects(): TrinaryLogic
 	{
+		if ($this->returnType->isVoid()->yes()) {
+			return TrinaryLogic::createYes();
+		}
+
 		return TrinaryLogic::createMaybe();
 	}
 

tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php

@@ -613,4 +613,10 @@ public function testPhpUnitIntegration(): void
 		$this->analyse([__DIR__ . '/../../Analyser/data/phpunit-integration.php'], []);
 	}
 
+	public function testBug8586(): void
+	{
+		$this->checkAlwaysTrueStrictComparison = true;
+		$this->analyse([__DIR__ . '/data/bug-8586.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-8586.php

@@ -0,0 +1,38 @@
+<?php declare(strict_types = 1);
+
+namespace Bug8586;
+
+class Foo
+{
+	public function getString(): ?string
+	{
+		return '';
+	}
+}
+
+/**
+ * @method void refreshFromAnnotation(object $object)
+ */
+class EntityManager
+{
+	public function refresh(object $object): void
+	{
+	}
+}
+
+class HelloWorld
+{
+	public function sayHello(Foo $foo, EntityManager $em): void
+	{
+		\assert($foo->getString() === null);
+		$em->refreshFromAnnotation($foo);
+		\assert($foo->getString() !== null);
+	}
+
+	public function sayHello2(Foo $foo, EntityManager $em): void
+	{
+		\assert($foo->getString() === null);
+		$em->refresh($foo);
+		\assert($foo->getString() !== null);
+	}
+}