Misleading error when parsing doc expression with missing macro

[andrewcooke]

Parsing a documented function with a missing (undefined) macro gives an error related to the doc expression (which is valid):

andrew@laptop:/tmp> cat nasty.jl

"""this is a doc string"""
function myfunc()
    @doesnotexist begin
    end
end

andrew@laptop:/tmp> julia-0.4 nasty.jl
ERROR: LoadError: invalid doc expression:

function myfunc()
    $(Expr(:line, 4, symbol("/tmp/nasty.jl")))
    @doesnotexist begin
        end
end
 in include at ./boot.jl:261
 in include_from_node1 at ./loading.jl:304
 in process_options at ./client.jl:308
 in _start at ./client.jl:411
while loading /tmp/nasty.jl, in expression starting on line 7

Using

   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.4.1-pre+22 (2015-11-01 00:06 UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit 669222e (5 days old release-0.4)
|__/                   |  x86_64-suse-linux