Constructing a FieldVector with too many elements kills Julia

[rdeits]

Derived from https://discourse.julialang.org/t/crash-stackoverflow-when-calling-constructor-with-too-many-inputs/7116

Here's a simple example:

julia> struct Foo{T} <: FieldVector{2, T}
         x::T
         y::T
       end

julia> Foo{Int}(1,2,3)
# Julia crashes here, presumably due to stack overflow

I believe there's an easy fix. I'll open a PR.

[rdeits]

The fact that Julia crashes instead of throwing a proper StackOverflow exception is probably because I'm on a mac: JuliaLang/julia#23126 (comment)

[DNF2]

I'm still having some problems here:

julia> Pkg.status("StaticArrays")
 - StaticArrays                  0.6.6+             master

julia> using StaticArrays

julia> struct Dummy2D{T<:Real} <: FieldVector{3, T}
           x::T
           y::T
           z::T
           Dummy2D{T}(x, y) where {T} = new{T}(x, y, one(T))
       end

julia> Dummy2D(1,2,3,4)
ERROR: No precise constructor for Dummy2D found. Length of input was 4.
Stacktrace:
 [1] Dummy2D(::Int64, ::Int64, ::Int64, ::Int64) at /Users/dnf/.julia/v0.6/StaticArrays/src/convert.jl:3

julia> Dummy2D(1,2,3)
Segmentation fault: 11

[rdeits]

Perhaps it's worth revisiting the question in this comment:

StaticArrays.jl/src/FieldVector.jl

Line 19 in 68eca4c

# Is this a good idea?? Should people just define constructors that accept tuples?