[longlivedeath]

> it is considered good practice to add types as documentation to top-level constructs

But with type inference your tools can do that for you (e.g. C-u C-c C-t in haskell-mode).

[lmm]

A good IDE can fill in the types in C++ too.

[longlivedeath]

Is there a C++ IDE that can figure out the function signature after you have written something like

_ f(_ a, _ b, _ c) { YOUR; CODE; HERE; }

?