stripe identity off ComposedOptic when test equality

src/varname.jl

@@ -151,7 +151,23 @@ end
 
 Base.hash(vn::VarName, h::UInt) = hash((getsym(vn), getoptic(vn)), h)
 function Base.:(==)(x::VarName, y::VarName)
-    return getsym(x) == getsym(y) && getoptic(x) == getoptic(y)
+    if getsym(x) !== getsym(y)
+        return false
+    end
+    o1, o2 = map((getoptic(x), getoptic(y))) do o
+        if o isa ComposedOptic
+            if o.inner == identity
+                return o.outer
+            elseif o.outer == identity
+                return o.inner
+            else
+                return o
+            end
+        else
+            return o
+        end
+    end
+    return o1 == o2
 end
 
 function Base.show(io::IO, vn::VarName{sym,T}) where {sym,T}

test/varname.jl

@@ -50,6 +50,14 @@ end
         @test test_equal(@varname(x.a[1:end, end][:], true), @varname(x.a[1:3,2][1:3]))
     end
 
+    @testset "equality" begin
+        vn1 = VarName{:a}(IndexLens(1) ∘ identity)
+        vn2 = VarName{:a}(IndexLens(1))
+        vn3 = VarName{:a}(identity ∘ IndexLens(1))
+        @test vn1 == vn2
+        @test vn1 == vn3
+    end
+
     @testset "get & set" begin
         x = (a = [1.0 2.0; 3.0 4.0; 5.0 6.0], b = 1.0);
         @test get(x, @varname(a[1, 2])) == 2.0