See also magicalhippo’s comment on overloading. We could introduce real types instead of primitives, so that ‘number_formatting_base_t’ would conflict with ‘array_index_t’, but nobody in the world bothers beyond bare ‘int’.

Yeah, I see the point, in for example C# if you have overloaded methods it tries it best to map it to the accepted type. However you'd have to work really hard to invent a case where a library updates a signature to accept another type, and then you in your code have 2 overloads of a method that you pass and it now choses the wrong version, all while the library change doesn't break any other code.

Scenario: Library changes signature so you always pass functions with more parameters.

Result: This will break almost every codebase, they probably wouldn't do this in a minor patch.

Scenario: Library adds a new signature where you can pass functions with more parameters and keep them overloaded between each other.

Result: Compiler can't identify which of the two signatures to pass your overloaded function and throws a compilation error.

Actually, that's what I use inline types in kotlin for.

So username, password are distinct from string and objectid might be backed by an int, but is distinct from int.

Obviously, once compiled, there's no overhead, it's a zero cost abstraction. But an incredibly useful one.

On my personal projects with F#, never got a chance to use it professionally, I actually use them. Makes modeling the data much easier.

Not including TypeScript.

Just to clarify, if you update toReadableNumber to take a second parameter and that parameter is not a number, typescript will complain.*

TypeScript won't catch the original landmine because it ignores the extra parameters; maybe some linter would? Is there a rule that enforces "functions used by map must spell out all the parameters?"

* Example of typescript giving an error on toReadableNumber_v2: https://www.typescriptlang.org/play?#code/FAYw9gdgzgLgBAQwE5...