One of my favorite things about F# is what some would consider a deficiency: that within a project, files must be ordered and you may only refer to a symbol defined earlier, with the sole exception of types which are explicitly declared together in a single statement (`type X = ... and Y = ...`).

This in contrast to C# where, within one .csproj, there is no "order" and all classes and methods are able to mutually reference one another.

The F# way creates an annoying housekeeping step of maintaining file order, and would be a nightmare to do with manually edited .fsproj files (I have only ever written F# with an IDE), but IMO, it is worth it. On the reading side, it makes it easier to understand how a project you've never read before is structured, since you know the order of the F# source files also must be the bottom-to-top layering of the code. On the writing side, it sometimes causes one to rethink the architecture and simplify it to minimize the number of mutual declarations.