# Known limitations and future work > The following are known limitations in the current implementation that may be addressed in future versions. Website: https://harnlang.com/spec/language/33-known-limitations-and-future-work.html This page documents Harn, which is pre-1.0. Language, standard library, and CLI APIs may change. If the intended version is unclear, clarify before using this page. --- ## Known limitations and future work The following are known limitations in the current implementation that may be addressed in future versions. ### Type system - **Definition-site generic checking**: Inside a generic function body, type parameters are treated as compatible with any type. The checker does not yet restrict method calls on `T` to only those declared in the `where` clause interface. - **No runtime interface enforcement**: Interface satisfaction is checked at compile-time only. Passing an untyped value to an interface-typed parameter is not caught at runtime. ### Runtime ### Syntax limitations - **No `impl Interface for Type` syntax**: Interface satisfaction is always implicit. There is no way to explicitly declare that a type implements an interface. --- ## Read next - [Environment variables](https://harnlang.com/spec/language/32-environment-variables.md) - [Platform support](https://harnlang.com/platform-support.md)