TypeError precompiling ImageQuilting.jl `Tuple: in non-final parameter, expected Type{T}, got Type{Vararg{ParserCombinator.Drop,N}}`

[tkelman]

seen in #18276 (comment), bisected to b0e692a

tkelman2@nanosoldier3:~/Julia/julia-0.6$ ./julia -e 'versioninfo(); Pkg.test("ImageQuilting")'
Julia Version 0.6.0-dev.545
Commit fd679b9 (2016-09-08 03:35 UTC)
Platform Info:
  System: Linux (x86_64-linux-gnu)
  CPU: Intel(R) Xeon(R) CPU E3-1241 v3 @ 3.50GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.7.1 (ORCJIT, haswell)
INFO: Testing ImageQuilting
WARNING: could not import Base.complement into LightGraphs
ERROR: LoadError: TypeError: Tuple: in non-final parameter, expected Type{T}, got Type{Vararg{ParserCombinator.Drop,N}}
 in _include_from_serialized(::String) at ./loading.jl:150
 in _require_from_serialized(::Int64, ::Symbol, ::String, ::Bool) at ./loading.jl:187
 in _require_search_from_serialized(::Int64, ::Symbol, ::String, ::Bool) at ./loading.jl:217
 in require(::Symbol) at ./loading.jl:402
 in _include_from_serialized(::String) at ./loading.jl:150
 in _require_from_serialized(::Int64, ::Symbol, ::String, ::Bool) at ./loading.jl:187
 in require(::Symbol) at ./loading.jl:425
 in include_from_node1(::String) at ./loading.jl:541
 in macro expansion; at ./none:2 [inlined]
 in anonymous at ./<missing>:?
 in eval(::Module, ::Any) at ./boot.jl:234
 in process_options(::Base.JLOptions) at ./client.jl:239
 in _start() at ./client.jl:326
while loading /home/tkelman2/.julia/v0.6/ImageQuilting/src/ImageQuilting.jl, in expression starting on line 22
ERROR: LoadError: Failed to precompile ImageQuilting to /home/tkelman2/.julia/lib/v0.6/ImageQuilting.ji.
 in compilecache(::String) at ./loading.jl:663
 in require(::Symbol) at ./loading.jl:453
 in include_from_node1(::String) at ./loading.jl:541
 in process_options(::Base.JLOptions) at ./client.jl:262
 in _start() at ./client.jl:326
while loading /home/tkelman2/.julia/v0.6/ImageQuilting/test/runtests.jl, in expression starting on line 1
===============================[ ERROR: ImageQuilting ]================================

failed process: Process(`/home/tkelman2/Julia/julia-0.6/usr/bin/julia -Cx86-64 -J/home/tkelman2/Julia/julia-0.6/usr/lib/julia/sys.so --compile=yes --depwarn=yes --check-bounds=yes --code-coverage=none --color=no --compilecache=yes /home/tkelman2/.julia/v0.6/ImageQuilting/test/runtests.jl`, ProcessExited(1)) [1]

=======================================================================================
ERROR: ImageQuilting had test errors
 in #test#61(::Bool, ::Function, ::Array{AbstractString,1}) at ./pkg/entry.jl:740
 in (::Base.Pkg.Entry.#kw##test)(::Array{Any,1}, ::Base.Pkg.Entry.#test, ::Array{AbstractString,1}) at ./<missing>:0
 in (::Base.Pkg.Dir.##2#3{Array{Any,1},Base.Pkg.Entry.#test,Tuple{Array{AbstractString,1}}})() at ./pkg/dir.jl:31
 in cd(::Base.Pkg.Dir.##2#3{Array{Any,1},Base.Pkg.Entry.#test,Tuple{Array{AbstractString,1}}}, ::String) at ./file.jl:69
 in #cd#1(::Array{Any,1}, ::Function, ::Function, ::Array{AbstractString,1}, ::Vararg{Array{AbstractString,1},N}) at ./pkg/dir.jl:31
 in (::Base.Pkg.Dir.#kw##cd)(::Array{Any,1}, ::Base.Pkg.Dir.#cd, ::Function, ::Array{AbstractString,1}, ::Vararg{Array{AbstractString,1},N}) at ./<missing>:0
 in #test#3(::Bool, ::Function, ::String, ::Vararg{String,N}) at ./pkg/pkg.jl:258
 in test(::String, ::Vararg{String,N}) at ./pkg/pkg.jl:258
 in eval(::Module, ::Any) at ./boot.jl:234
 in process_options(::Base.JLOptions) at ./client.jl:239
 in _start() at ./client.jl:326

edit: the tests pass when started with --compilecache=no