Index: src/runtime/class.m
==================================================================
--- src/runtime/class.m
+++ src/runtime/class.m
@@ -844,10 +844,13 @@
 	struct objc_object *object;
 
 	if (object_ == nil)
 		return Nil;
 
+	if (object_isTaggedPointer(object_))
+		return object_getTaggedPointerClass(object_);
+
 	object = (struct objc_object *)object_;
 
 	return object->isa;
 }
 

Index: src/runtime/private.h
==================================================================
--- src/runtime/private.h
+++ src/runtime/private.h
@@ -333,10 +333,18 @@
 	uint8_t j = idx;
 
 	return dtable->buckets[i]->buckets[j];
 #endif
 }
+
+static inline bool
+object_isTaggedPointer(id _Nullable object)
+{
+	uintptr_t pointer = (uintptr_t)object;
+
+	return pointer & 1;
+}
 
 #if defined(OF_ELF)
 # if defined(OF_X86_64) || defined(OF_X86) || defined(OF_POWERPC) || \
     defined(OF_ARM64) || defined(OF_ARM) || \
     defined(OF_MIPS64_N64) || defined(OF_MIPS) || \