diff --git a/common/src/main/kotlin/fr/username404/snowygui/Snowy.kt b/common/src/main/kotlin/fr/username404/snowygui/Snowy.kt
index 2e17773..f757a08 100644
--- a/common/src/main/kotlin/fr/username404/snowygui/Snowy.kt
+++ b/common/src/main/kotlin/fr/username404/snowygui/Snowy.kt
@@ -19,7 +19,7 @@ abstract class Snowy {
         val Gson: Gson = GsonBuilder().excludeFieldsWithoutExposeAnnotation().create()
         @JvmStatic
         protected val FeaturePackage: String = "fr.username404.snowygui.gui.feature"
-        lateinit var annotatedButtons: Set<Class<ButtonImpl>>
+        lateinit var annotatedButtons: Set<Class<out ButtonImpl>>
         fun onEvent(e: String, lambda: argsLambda) = useKey(e).add(lambda)
         @JvmField
         val logs: Logger = LogManager.getLogger()
diff --git a/fabric/src/main/kotlin/fr/username404/snowygui/fabric/FabricInit.kt b/fabric/src/main/kotlin/fr/username404/snowygui/fabric/FabricInit.kt
index 7e32691..aadb9cf 100644
--- a/fabric/src/main/kotlin/fr/username404/snowygui/fabric/FabricInit.kt
+++ b/fabric/src/main/kotlin/fr/username404/snowygui/fabric/FabricInit.kt
@@ -30,6 +30,6 @@ class FabricInit: Snowy(), ClientModInitializer {
                 .setUrls(ClasspathHelper.forPackage(FeaturePackage))
                 .setScanners(SubTypesScanner(false), TypeAnnotationsScanner())
                 .useParallelExecutor()
-        ).getTypesAnnotatedWith(ButtonInfo::class.java).filter { it.isValidForButtonCollection() }.toSet() as Set<Class<ButtonImpl>>
+        ).getTypesAnnotatedWith(ButtonInfo::class.java).filter { it.isValidForButtonCollection() }.map { it.asSubclass(ButtonImpl::class.java) }.toSet()
     }
 }
\ No newline at end of file
diff --git a/forge/src/main/kotlin/fr/username404/snowygui/forge/ForgeInit.kt b/forge/src/main/kotlin/fr/username404/snowygui/forge/ForgeInit.kt
index 2045b46..eca98ed 100644
--- a/forge/src/main/kotlin/fr/username404/snowygui/forge/ForgeInit.kt
+++ b/forge/src/main/kotlin/fr/username404/snowygui/forge/ForgeInit.kt
@@ -50,7 +50,7 @@ class ForgeInit: Snowy() {
                     }
                 }
             }
-            .map { Class.forName((it!!.javaClass.getDeclaredField("clazz").apply { isAccessible = true }.get(it) as Type).className) as Class<ButtonImpl> }
+            .map { Class.forName((it!!.javaClass.getDeclaredField("clazz").apply { isAccessible = true }.get(it) as Type).className).asSubclass(ButtonImpl::class.java)}
             .collect(Collectors.toSet())
         with(MOD_BUS) {
             addListener(this@ForgeInit::initSetup)