The state of the art is Idris, which has a sound, decidable, and extremely powerful type system. Most state of the art mainstream languages like Rust have sound

The state of the art is Idris, which has a sound, decidable, and extremely powerful type system. Most state of the art mainstream languages like Rust have sound but undecidable type systems. Many older languages with ad-hoc type systems are unsound, but there are also some older relatively used languages with powerful and sound type systems like Haskell.