There are at least a few nascent statically typed languages (as in, full static typing rather than gradual) which nevertheless let code with type errors compile

There are at least a few nascent statically typed languages (as in, full static typing rather than gradual) which nevertheless let code with type errors compile for the sake of testing. The two that I know of are Darklang [0] and Roc [1] which aim to let you compile code with type errors for the same reason you suggest. [0] "Dark is designed for continuous delivery. As such, we don’t like requiring you to make large scale changes across your program, like changing a type everywhere. Instead, we want you to quickly discover that bad ideas won’t work, without first requiring you to propagate the type changes throughout your program." https://blog.darklang.com/real-problems-with-functional-languages/ https://blog.darklang.com/real-problems-with-functional-lang... [1] "If you like, you can run a program that has compile-time errors like this. (If the program reaches the error at runtime, it will crash.)" https://www.roc-lang.org/friendly https://www.roc-lang.org/friendly