How to use a qualified operator?

[AZMCode]

I've been trying out the relatively (I took a while to get here) new implicit arguments, and they've been great so far, but I've fallen into a syntax error problem trying to use them.

Suppose I am defining a function, with an implicit operator argument as follows:

pub fun myfunc(a: int64, b: int64,?qualified/(+): (int64, int64) -> total int64): int64
    a ?qualified/(+) b

This code yields a

invalid syntax
unexpected identifier (operator) "@implicit/qualified/(+)"
expecting ".", "(", "[", "{", "fn", operator, ":=", ";", "return" or "}"

error.
Is there a way to use the operator without removing the qualification?

Edit: On second look it appears the argument being implicit has nothing to do with this

[AZMCode]

I have found that using

(?qualified/(+))(a,b)

Works, but it is quite verbose

[chtenb]

I don't think you're supposed to write the question mark at the call site. This also compiles:

pub fun myfunc(a: int64, b: int64,?qualified/(+): (int64, int64) -> total int64): int64
  qualified/(+)(a, b)