Nullables test error on 1.1.0 branch

[KristofferC]

Repro is:

julia> using Nullables

julia> isequal(Nullable{Bool}(), Nullable(Int8(0)))
ERROR: zext_int: value is not a primitive type
Stacktrace: [1] toInt8 at ./boot.jl:627 [inlined]
 [2] Type at ./boot.jl:730 [inlined]
 [3] convert at ./number.jl:7 [inlined]
 [4] _promote at ./promotion.jl:261 [inlined]
 [5] promote at ./promotion.jl:284 [inlined]
 [6] == at ./promotion.jl:350 [inlined]
 [7] isequal at ./operators.jl:123 [inlined]
 [8] isequal(::Nullable{Bool}, ::Nullable{Int8}) at /Users/kristoffer/.julia/dev/Nullables/src/nullable.jl:244
 [9] top-level scope at none:0

[KristofferC]

Removing using Compat from Nullables make the error go away.

[KristofferC]

"MWE" :

using Compat

struct Nullable{T}
    hasvalue::Bool
    value::T
    Nullable{T}() where {T} = new(false)
    Nullable{T}(value::T, hasvalue::Bool=true) where {T} = new(hasvalue, value)
end

@inline function Base.isequal(x::Nullable{S}, y::Nullable{T}) where {S,T}
    isequal(x.value, y.value)
end

isequal(Nullable{Bool}(), Nullable{Int8}(Int8(0)))

(this seems to just hang in stead).

[StefanKarpinski]

Since we don't seem to have a "blocker" tag, I've put "priority" on this—this is causing breakage in released packages, which means this blocks the release of 1.1.