[gleenn]

That's my point, the type errors being reduced isn't that interesting, I usually find and fix those extremely quickly. What I don't find but am most interested in is the actual logic. So I must write tests. And when I write tests, I get the type errors covered too. So why should I spend my precious time modeling inside a type system when the ROI is minuscule and the cost is I have to litter my codebase with types. Just write the tests.

[ninetyninenine]

You can write the test in the type system with dependent types. It's the same thing. But your language needs to support this. Typescript supports it. The static analyzer in your ide or during compilation will now run the test. You get a model and a test for free.