Zygote AD fails

[tpapp]

import Zygote
using TransformVariables
f(y) = y.mu + y.sigma
t = as((mu  = as(Real, -25, 25), sigma = asℝ₊), )
Zygote.gradient(f ∘ t, zeros(2))
(f∘t)(zeros(2))

(this is the MWE for tpapp/LogDensityProblems.jl#43 (comment))

@itsdfish

[devmotion]

With TransformVariables#master and Zygote@0.7.4 I get:

julia> Zygote.gradient(f ∘ transform(t), zeros(2))
([12.5, 1.0],)

julia> FiniteDifferences.grad(central_fdm(5, 1), f ∘ transform(t), zeros(2))
([12.499999999993662, 0.9999999999999681],)

julia> (f∘transform(t))(zeros(2))
1.0