push! does not check for column length consistency

Are these two scenarios intended?

julia> t = StructArray([(a=1,b=2)])
1-element StructArray(::Array{Int64,1}, ::Array{Int64,1}) with eltype NamedTuple{(:a, :b),Tuple{Int64,Int64}}:
 (a = 1, b = 2)

julia> push!(t,(a=2,b="3"))
ERROR: MethodError: Cannot `convert` an object of type String to an object of type Int64

julia> t
2-element StructArray(::Array{Int64,1}, ::Array{Int64,1}) with eltype NamedTuple{(:a, :b),Tuple{Int64,Int64}}:
 (a = 1, b = 2)
 (a = 2, b = 140572479985616)


julia> t = StructArray([(a=1,b="2")])
1-element StructArray(::Array{Int64,1}, ::Array{String,1}) with eltype NamedTuple{(:a, :b),Tuple{Int64,String}}:
 (a = 1, b = "2")

julia> push!(t,(a=2,b=3))
ERROR: MethodError: Cannot `convert` an object of type Int64 to an object of type String

julia> t
2-element StructArray(::Array{Int64,1}, ::Array{String,1}) with eltype NamedTuple{(:a, :b),Tuple{Int64,String}}:
Error showing value of type StructArray{NamedTuple{(:a, :b),Tuple{Int64,String}},1,NamedTuple{(:a, :b),Tuple{Array{Int64,1},Array{String,1}}},Int64}:

(I could not find this case noted in other places - it seems for me to be a bug, but maybe it is intended for performance reasons?)

Start by reproducing both push! examples with StructArray values having incompatible column types. Inspect the push! entry point and related tests, then verify that a failed insertion does not change the array or leave it in an invalid state.