Long recompilation delay with finicky dependencies

[timholy]

Continuing from #21173 (comment). This is about as minimal as I was able to find (commenting almost anything out, including docstrings, eliminates the issue):

__precompile__(true)

module CoordTforms

using StaticArrays

abstract type Transformation end

#############################
### 2D Coordinate systems ###
#############################
"""
`Polar{T}(r::T, θ::T)` - 2D polar coordinates
"""
immutable Polar{T}
    r::T
    θ::T
end

"`PolarFromCartesian()` - transformation from `AbstractVector` of length 2 to `Polar` type"
immutable PolarFromCartesian <: Transformation; end
"`CartesianFromPolar()` - transformation from `Polar` type to `SVector{2}` type"
immutable CartesianFromPolar <: Transformation; end

function (::PolarFromCartesian)(x::AbstractVector)
    length(x) == 2 || error("Polar transform takes a 2D coordinate")

    Polar(sqrt(x[1]*x[1] + x[2]*x[2]), atan2(x[2], x[1]))
end

function (::CartesianFromPolar)(x::Polar)
    SVector(x.r * cos(x.θ), x.r * sin(x.θ))
end

Base.convert(::Type{Polar}, v::AbstractVector) = PolarFromCartesian()(v)
@inline Base.convert{V <: AbstractVector}(::Type{V}, p::Polar) = convert(V, CartesianFromPolar()(p))


#############################
### 3D Coordinate Systems ###
#############################
"""
Spherical(r, θ, ϕ) - 3D spherical coordinates
"""
immutable Spherical{T}
    r::T
    θ::T
    ϕ::T
end

end

Now if you do

julia> push!(LOAD_PATH, pwd())
3-element Array{Any,1}:
 "/home/tim/src/julia-0.6/usr/local/share/julia/site/v0.6"
 "/home/tim/src/julia-0.6/usr/share/julia/site/v0.6"      
 "/tmp"                                                   

julia> using CoordTforms

and then hit one key, TAB, and a second key, you'll see a very long delay.

[timholy]

It's worth noting that none of the code in CoordTforms uses StaticArrays. Yet if you comment out the using StaticArrays from inside CoordTforms.jl, the big delay goes away even if you load StaticArrays at the REPL.