Default values for macros

[hayd]

The following syntax doesn't work for macros (but does for functions):

julia> macro foo(a, b::Bool=true)
          a, b
       end
ERROR: syntax: "(kw (:: b Bool) #t)" is not a valid function argument name

julia> function foo(a, b::Bool=true)  #works for functions
          a, b
       end
foo (generic function with 2 methods)

julia> foo(1)
(1,true)

[ihnorton]

Seems unnecessary IMHO (varargs work fine), but I guess it is arguably more consistent. The error message could at least be improved.

[JeffBezanson]

This is basically a duplicate (or special case) of #8846.