invocant error message

$ perl6 -e 'class A { method foo($x) {} }; A.foo'

What it looks like now:

Not enough positional parameters passed; got 1 but expected 2
  in 'A::foo' at line 1
  in main program body at line 1

What I'd like it to be:

Not enough positional parameters passed; got invocant+0 but expected invocant+1
  in 'A::foo' at line 1
  in main program body at line 1

Or, possibly:

Not enough positional parameters passed; got 1 but expected 2 (the invocant included)
  in 'A::foo' at line 1
  in main program body at line 1

But I think I like the former better, since the latter is ambiguous as to how many
of the numbers the parenthetical qualifier applies to.