Different analysis of a method call depending on parentheses

[DedSec256]

open System

let f x  = (DateTime.UtcNow.ToBinary) x
let f x = DateTime.UtcNow.ToBinary x

Expected behavior

Behavior is consistent between both cases. (Correct type inference and no errors in the second case?)

[LyndonGingerich]

I think my issue at fsharp/fslang-suggestions#1208 is probably a duplicate of yours, though I approached the question rather differently, so I'm closing it.

My findings:

• You can't directly pass a single bound parameter of type unit into a member.
• You can pipe such a value into a member. This is an alternate workaround to parenthesizing the member.

A helpful comment from @kerams:

There's a dissonance between what x.Method () means in F#, and functional programming in general, conceptually (passing in one argument of type unit, which is why I prefer to add that extra space), and how it is represented in .NET (calling a method with no arguments). My guess is that the compiler looks for methods with 0 parameters when the () constant is passed in. In your case the constant is hidden and method resolution looks for a method with 1 parameter.

[vzarytovskii]

This probably should go via suggestions and @dsyme's review.

[dsyme]

Yes this is by design, the comment from @kerams above is correct