But doesn't change the tests you need to write, and those tests are going to incidentally cover anything the type system is also going to catch, so the type system isn't going to somehow make your software more reliable.
A much more expressive type system can get you there, but you won't find that in any language anyone actually uses on a normal basis.
You still need tests for functionality (this function does what it should) but the type system removes many error cases automatically.