Support more optional 3.29 features

Author: fredemmott

.hhconfig

@@ -6,3 +6,6 @@ disallow_unsafe_comparisons=true
 decl_override_require_hint=true
 enable_experimental_tc_features=shape_field_check,sealed_classes
 forward_compatibility_level=3.29
+user_attributes=
+disable_primitive_refinement=true
+disallow_stringish_magic=true

composer.lock

@@ -42,8 +42,6 @@ public function getType(): string {
        return $this->type->render();
      }
 
-     invariant($this->type !== null, "Somehow type is null");
-     invariant(is_string($this->type), "Somehow type is not a string");
-     return $this->type;
+     return $this->type as string;
    }
  }