esc cannot be used in function arguments

[MikeInnes]

module Foo
macro iter()
  quote
    @inline function Base.start(sub)
      it = 1
    end
  end
end
end

Macroexpanding Foo.@iter yields a function with an argument Foo.sub and a local Foo.it, both of which are broken.

In fewer cases (but still in this case) 0.4 also qualifies sub, but gensyms it correctly.

[yuyichao]

Ref #10887

[MikeInnes]

Another issue is that without the inline macro it's not possible to escape function argument names. I don't think that's a regression though (I think I might have seen an issue for it somewhere).

[vtjnash]

looks like it's still broken / the fix broke something else: http:https://buildbot.e.ip.saba.us:8010/builders/perf_nanosoldier-x64/builds/201

[JeffBezanson]

I can reproduce that on 0.4:

julia> macro foo()
        quote
         function foo($(esc(:x)))
           x
         end
       end
       end

julia> @foo
ERROR: syntax: "(escape x)" is not a valid function argument name

Maybe there was some intermediate time where it worked on master.

[MikeInnes]

Also, I'm not able to escape the entire signature when using block syntax:

:($(:(f())) = 1) # works
:(function $(:(f())) 1 end) # syntax: expected "end" in definition of function "($ '(call f))"