diff --git a/src/gen_stub.php b/src/gen_stub.php
index 25774959..d6746cc7 100755
--- a/src/gen_stub.php
+++ b/src/gen_stub.php
@@ -207,8 +207,6 @@ class ArrayType extends SimpleType {
             return false;
         }
 
-        assert(get_class($other) === self::class);
-
         return Type::equals($this->keyType, $other->keyType) &&
             Type::equals($this->valueType, $other->valueType);
     }
diff --git a/version.txt b/version.txt
index ca883787..c500a5fe 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-1055
+1057