Support Dual{T}(x)

src/dual.jl

@@ -6,6 +6,7 @@ struct Dual{T<:ReComp} <: Number
 end
 Dual(x::S, y::T) where {S<:ReComp,T<:ReComp} = Dual(promote(x,y)...)
 Dual(x::ReComp) = Dual(x, zero(x))
+Dual{T}(x::ReComp) where T<:ReComp = Dual{T}(T(x), zero(T))
 
 const ɛ = Dual(false, true)
 const imɛ = Dual(Complex(false, false), Complex(false, true))

test/automatic_differentiation_test.jl

@@ -25,6 +25,7 @@ y = abs(-x)
 @test epsilon(y) ≈ 1.0
 
 @test isequal(1.0,Dual(1.0))
+@test Dual{Float32}(3) === Dual{Float32}(3.0f0, 0.0f0)
 
 y = 1/x
 @test value(y) ≈ 1/2

test/runtests.jl

@@ -1,6 +1,8 @@
 using DualNumbers
 using Test
 
+@test isempty(detect_ambiguities(DualNumbers, Base, Core))
+
 @test checkindex(Bool, 1:3, dual(2))
 
 # wrap in individual modules to avoid name conflicts.