[mattgreenrocks]

Type inference is powerful but probably too powerful for module-level (e.g. global) declarations.

Despite type systems being powerful enough to figure out what types should be via unification, I don't think asking programmers to write the types of module declarations is too much. This is one area where forcing work on the programmer is really useful to ensure that they are tracking boundary interface changes correctly.

[BoppreH]

People accept manually entering types only at a relatively high level. It'd be different if types were "function that takes a non-empty list of even numbers between 2 and 100, and a possibly tainted non-negative non-NaN float in meters/second, returning a length-4 alphanumeric string without side effects in O(n)".