show methods cause unhandled exception errors on master

[andreasnoack]

This might be Julia's fault but I was unable to make a simpler example

julia> SMatrix
Error showing value of type UnionAll:
ERROR: UndefVarError: N not defined
Stacktrace:
 [1] show(::IOContext{Base.Terminals.TTYTerminal}, ::Type{SYSTEM: show(lasterr) caused an error
UndefVarError(:N)

Stacktrace:
 [1] show(::IOContext{Base.Terminals.TTYTerminal}, ::Type{ERROR: UndefVarError: N not defined
Stacktrace:
 [1] show(::IOContext{Base.Terminals.TTYTerminal}, ::Type{fatal: error thrown and no exception handler available.
UndefVarError(var=:N)
rec_backtrace at /Users/andreasnoack/julia-dev/src/stackwalk.c:86
record_backtrace at /Users/andreasnoack/julia-dev/src/task.c:246 [inlined]
jl_throw at /Users/andreasnoack/julia-dev/src/task.c:568
jl_undefined_var_error at /Users/andreasnoack/julia-dev/src/rtutils.c:129
show at /Users/andreasnoack/.julia/v0.7/StaticArrays/src/SMatrix.jl:60
show_datatype at ./show.jl:228
show at ./show.jl:210
print at ./strings/io.jl:30
print at ./strings/io.jl:41
show_tuple_as_call at ./show.jl:1114
show_spec_linfo at ./stacktraces.jl:217
#show#9 at ./stacktraces.jl:225
unknown function (ip: 0x10ee6c005)
#show at ./<missing>:0
#show_trace_entry#516 at ./replutil.jl:624
unknown function (ip: 0x10ee6b3b1)
#show_trace_entry at ./<missing>:0
#518 at ./replutil.jl:641
unknown function (ip: 0x10ee6ad1c)
#process_backtrace#521 at ./replutil.jl:672
unknown function (ip: 0x10ee6a7ec)
show_backtrace at ./replutil.jl:644
#showerror#498 at ./replutil.jl:223
unknown function (ip: 0x10ee691f9)
showerror at ./replutil.jl:218
display_error at ./client.jl:139
display_error at ./client.jl:142
do_call at /Users/andreasnoack/julia-dev/src/interpreter.c:70
eval at /Users/andreasnoack/julia-dev/src/interpreter.c:262
eval_body at /Users/andreasnoack/julia-dev/src/interpreter.c:539
jl_toplevel_eval_body at /Users/andreasnoack/julia-dev/src/interpreter.c:511
jl_toplevel_eval_flex at /Users/andreasnoack/julia-dev/src/toplevel.c:602
jl_toplevel_eval_in at /Users/andreasnoack/julia-dev/src/builtins.c:505
eval at ./sysimg.jl:48
_start at ./client.jl:429
true_main at /Users/andreasnoack/bin/julia-dev (unknown line)
main at /Users/andreasnoack/bin/julia-dev (unknown line)

on

Julia Version 0.7.0-DEV.1327
Commit 104dce7fcf* (2017-08-11 16:01 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin16.7.0)
  CPU: Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT NO_AFFINITY HASWELL)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.9.1 (ORCJIT, haswell)
Environment:

[kshyatt]

Don't we not have show defined for most of our types? Maybe we should do that...

[tkoolen]

FYI: this is not fixed by #296.

[c42f]

This no longer seems to be a problem.