Elixir v1.20 Released: Now a Gradually Typed Language
Original: Elixir v1.20: Now a gradually typed language
Why This Matters
Major programming language evolution adding type safety while maintaining backward compatibility
Elixir v1.20 introduces set-theoretic types with gradual type checking, performing type inference without annotations. The release enables detection of dead code and verified bugs with low false positives.
Elixir v1.20 completes the first milestone of adding set-theoretic types to the programming language, announced in 2022. The type system performs type inference and gradual type checking on all Elixir programs without requiring type annotations. It introduces the dynamic() type with compatibility and narrowing properties, different from any() types in other gradual systems. The implementation finds verified bugs efficiently with extremely low false positive rates. Elixir passes 12 of 13 categories in the "If T: Benchmark for Type Narrowing" test, demonstrating precise type information recovery. The type system development was made possible through a partnership between CNRS and Remote, currently sponsored by Fresha and Tidewave.