Indexing problem with generated LazyJSON.String object

[lwabeke]

Hi

I was trying to see how compatible LazyJSON would be with my Unmarshal.jl package.
While trying to get it to work, I believe I found a few problems in the Unmarshal package, that is being addressed, but I also found some problems with LazyJSON.

getindex works with a string, but not with a LazyJSON.String{String}.

Here is a minimum working example:

julia> using JSON, LazyJSON

julia> d = Dict("2" => "Test2","1" => "Test1")
Dict{String,String} with 2 entries:
  "1" => "Test1"
  "2" => "Test2"

julia> jl = LazyJSON.parse(JSON.json(d))
LazyJSON.Object{Nothing,String} with 2 entries:
  "1" => "Test1"
  "2" => "Test2"

julia> jl["1"]
"Test1"

julia> k = collect(keys(jl))[1]
"1"

julia> typeof(k)
LazyJSON.String{String}

julia> jl[k]
ERROR: MethodError: no method matching pointer(::LazyJSON.String{String})
Closest candidates are:
  pointer(::String) at strings/string.jl:81
  pointer(::String, ::Integer) at strings/string.jl:82
  pointer(::SubString{String}) at strings/substring.jl:109
  ...
Stacktrace:
 [1] get_ic(::LazyJSON.Object{Nothing,String}, ::LazyJSON.String{String}, ::Tuple{Int64,UInt8}, ::Int64) at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/LazyJSON.jl:343
 [2] get_ic at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/LazyJSON.jl:327 [inlined]
 [3] _get at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/AbstractDict.jl:19 [inlined]
 [4] get at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/AbstractDict.jl:17 [inlined]
 [5] getindex(::LazyJSON.Object{Nothing,String}, ::LazyJSON.String{String}) at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/AbstractDict.jl:10
 [6] top-level scope at REPL[9]:1

julia> for iter keys(jl)
ERROR: syntax: invalid iteration specification
Stacktrace:
 [1] top-level scope at REPL[9]:0

julia> for iter in keys(jl)
         @show jl[iter]
         end
ERROR: MethodError: no method matching pointer(::LazyJSON.String{String})
Closest candidates are:
  pointer(::String) at strings/string.jl:81
  pointer(::String, ::Integer) at strings/string.jl:82
  pointer(::SubString{String}) at strings/substring.jl:109
  ...
Stacktrace:
 [1] get_ic(::LazyJSON.Object{Nothing,String}, ::LazyJSON.String{String}, ::Tuple{Int64,UInt8}, ::Int64) at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/LazyJSON.jl:343
 [2] get_ic at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/LazyJSON.jl:327 [inlined]
 [3] _get at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/AbstractDict.jl:19 [inlined]
 [4] get at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/AbstractDict.jl:17 [inlined]
 [5] getindex(::LazyJSON.Object{Nothing,String}, ::LazyJSON.String{String}) at /Users/lwabeke/.julia/packages/LazyJSON/EmafJ/src/AbstractDict.jl:10
 [6] macro expansion at ./show.jl:562 [inlined]
 [7] top-level scope at ./REPL[11]:2

I will try looking into a PR, but my first attempt at providing a method for Base.pointer(::LazyJSON.String{String}), resulted in a Julia segfault. Logging it here, in case someone else is quicker or I get distracted before being able to look at the PR