Remove unnecessary Ref()

Author: saschatimme

src/differentiation.jl

@@ -34,7 +34,7 @@ differentiate(α::T, v::AbstractVariable) where T = zero(T)
 differentiate(v1::AbstractVariable, v2::AbstractVariable) = v1 == v2 ? 1 : 0
 differentiate(t::AbstractTermLike, v::AbstractVariable) = coefficient(t) * differentiate(monomial(t), v)
 # The polynomial function will take care of removing the zeros
-differentiate(p::APL, v::AbstractVariable) = polynomial(differentiate.(terms(p), Ref(v)), SortedState())
+differentiate(p::APL, v::AbstractVariable) = polynomial(differentiate.(terms(p), v), SortedState())
 differentiate(p::RationalPoly, v::AbstractVariable) = (differentiate(p.num, v) * p.den - p.num * differentiate(p.den, v)) / p.den^2
 
 const ARPL = Union{APL, RationalPoly}

test/differentiation.jl

@@ -1,7 +1,7 @@
 @testset "Differentiation" begin
     Mod.@polyvar x y
     @test differentiate(3, y) == 0
-    @test differentiate.([x, y], Ref(y)) == [0, 1]
+    @test differentiate.([x, y], y) == [0, 1]
     @test differentiate([x, y], (x, y)) == Matrix(1.0I, 2, 2) # TODO: this can be just `I` on v0.7 and above
     @test differentiate(true*x+true*x^2, y) == 0
     @inferred differentiate(true*x+true*x^2, y)

test/example1.jl

@@ -2,7 +2,7 @@
     Mod.@polyvar x y
     p = 2x + 3.0x*y^2 + y
     @test differentiate(p, x) == 2 + 3y^2
-    @test differentiate.(Ref(p), (x, y)) == (2 + 3y^2, 6x*y + 1)
+    @test differentiate.(p, (x, y)) == (2 + 3y^2, 6x*y + 1)
     @test p((x, y)=>(y, x)) == 2y + 3y*x^2 + x
     @test subs(p, y=>x^2) == 2x + 3x^5 + x^2
     @test p(x=>1, y=>2) == 2 + 3*4 + 2