>Time is often better spend by writing testcases instead of chasing down type issues(more so if a language has a 'generics' or C++ templates concept), so that a

>Time is often better spend by writing testcases instead of chasing down type issues(more so if a language has a 'generics' or C++ templates concept), so that approach got favored in many fields. These will catch type errors, and static languages also need tests, so the gains are not so easily quantifiable. Assuming an equivalent program written in a statically-checked language and a dynamically-checked language, if your program has type errors at compile time, it will also have type errors at runtime. The difference is when you know about them. Static type checking is (informally) about statically proving that the domain of your function is actually what you think it is. They catch "obvious" (for a definition of obvious that is defined by the power of the type system) domain errors. They don't replace tests, but they do constrain the domain you need to test and let you know when your tests are sane.