Comment by ddellacosta

> The second type definition is there only to make developers write it wrong.

Int32 is the type of the return value for the function (https://doc.flix.dev/functions.html), which is distinct information not implied by the type being passed in (Shape), so I dispute this characterization--the fact that this type is the same type as the parameter given to all of Shape's terms is specific to this example. Furthermore I suspect it would immediately be caught by the typechecker regardless.

While in a language like Haskell you could define this function without a type definition and its type would be inferred (vs. in Flix, see https://doc.flix.dev/functions.html?highlight=inference#func...), regardless I will almost always declare the type of top-level functions (or even non-top-level functions) for clarity when reading the code. I think this is useful and important information in any case.