add constructorof for PropertyLens

Author: aplavin

src/optics.jl

@@ -392,6 +392,8 @@ The second constructor may not be type stable when `fieldname` is not a constant
 """
 @inline PropertyLens(fieldname) = PropertyLens{fieldname}()
 
+ConstructionBase.constructorof(::Type{PropertyLens{P}}) where {P} = PropertyLens{P}
+
 function (l::PropertyLens{field})(obj) where {field}
     getproperty(obj, field)
 end

test/test_optics.jl

@@ -93,9 +93,14 @@ end
     @inferred modify(x -> 0, arr, @optic _ |> Elements() |> If(iseven))
 end
 
-@testset "convenience constructors" begin
+@testset "constructors" begin
     @test IndexLens(1, 2, 3) === IndexLens((1, 2, 3))
     @test PropertyLens(:a) === PropertyLens{:a}()
+
+    f = PropertyLens(:a)
+    @test constructorof(typeof(f))(Accessors.getfields(f)...) === f
+    f = IndexLens(1, 2, 3)
+    @test constructorof(typeof(f))(Accessors.getfields(f)...) === f
 end
 
 @testset "broadcasting" begin