From 97a3e89689e14c7a0b1ed6153e28fca720a6238f Mon Sep 17 00:00:00 2001
From: Brad Carman <brad_carman@instron.com>
Date: Thu, 27 Oct 2022 13:27:09 -0400
Subject: [PATCH] code and test

---
 src/lens.jl       |  4 ++++
 test/test_core.jl | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/lens.jl b/src/lens.jl
index cbd4220..865b5b2 100644
--- a/src/lens.jl
+++ b/src/lens.jl
@@ -259,3 +259,7 @@ struct FunctionLens{f} <: Lens end
 FunctionLens(f) = FunctionLens{f}()
 
 get(obj, ::FunctionLens{f}) where f = f(obj)
+
+
+Base.hasproperty(obj, l::Setfield.ComposedLens) = hasproperty(obj, l.outer)
+Base.hasproperty(obj, l::PropertyLens{f}) where f = hasproperty(obj, f)
\ No newline at end of file
diff --git a/test/test_core.jl b/test/test_core.jl
index 867a259..3b87d56 100644
--- a/test/test_core.jl
+++ b/test/test_core.jl
@@ -518,4 +518,14 @@ end
     @test @lens(_.x[1, :].$(fancy(name, "✨"))) == @lens(_.x[1, :].fancy_a✨)
 end
 
+@testset "hasproperty" begin
+    obj = (x=1,)
+
+    l1 = @lens _.x
+    l2 = @lens _.y
+
+    @test hasproperty(obj, l1)
+    @test !hasproperty(obj, l2)
+end
+
 end