Bug-report: Example `similar` does not work

[schlichtanders]

Using julia 1.6.1 with Dictionaries v0.3.9, I get the following error when executing part of the README.md

julia> using Dictionaries

julia> dict = Dictionary(["a", "b", "c"], [1, 2, 3])
3-element Dictionary{String, Int64}
 "a" │ 1
 "b" │ 2
 "c" │ 3

julia> similar(dict, Vector{Int})
Error showing value of type Dictionary{String, Vector{Int64}}:
ERROR: UndefRefError: access to undefined reference
Stacktrace:
  [1] getindex
    @ ./array.jl:801 [inlined]
  [2] gettokenvalue
    @ ~/.julia/packages/Dictionaries/YpAxR/src/Dictionary.jl:288 [inlined]
  [3] iterate
    @ ~/.julia/packages/Dictionaries/YpAxR/src/AbstractDictionary.jl:52 [inlined]
  [4] isempty
    @ ./essentials.jl:767 [inlined]
  [5] show(io::IOContext{Base.TTY}, #unused#::MIME{Symbol("text/plain")}, d::Dictionary{String, Vector{Int64}})
    @ Dictionaries ~/.julia/packages/Dictionaries/YpAxR/src/show.jl:127
  [6] (::REPL.var"#38#39"{REPL.REPLDisplay{REPL.LineEditREPL}, MIME{Symbol("text/plain")}, Base.RefValue{Any}})(io::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:220
  [7] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
  [8] display(d::REPL.REPLDisplay, mime::MIME{Symbol("text/plain")}, x::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:213
  [9] display(d::REPL.REPLDisplay, x::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:225
 [10] display(x::Any)
    @ Base.Multimedia ./multimedia.jl:328
 [11] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
 [12] invokelatest
    @ ./essentials.jl:706 [inlined]
 [13] print_response(errio::IO, response::Any, show_value::Bool, have_color::Bool, specialdisplay::Union{Nothing, AbstractDisplay})
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:247
 [14] (::REPL.var"#40#41"{REPL.LineEditREPL, Pair{Any, Bool}, Bool, Bool})(io::Any)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:231
 [15] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [16] print_response(repl::REPL.AbstractREPL, response::Any, show_value::Bool, have_color::Bool)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:229
 [17] (::REPL.var"#do_respond#61"{Bool, Bool, REPL.var"#72#82"{REPL.LineEditREPL, REPL.REPLHistoryProvider}, REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::Any, ok::Bool)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:798
 [18] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
 [19] invokelatest
    @ ./essentials.jl:706 [inlined]
 [20] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/LineEdit.jl:2441
 [21] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:1126
 [22] (::REPL.var"#44#49"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL ./task.jl:411

Here my full versioninfo:

julia> versioninfo()
Julia Version 1.6.1
Commit 6aaedecc44 (2021-04-23 05:59 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-11.0.1 (ORCJIT, icelake-client)
Environment:
  JULIA_EDITOR = code-insiders
  JULIA_NUM_THREADS = 

[andyferris]

I actually fixed this one locally already but haven't pushed! Thanks for reminding me.

[andyferris]

Fixed in the 0.3.10 release.