fix itr for fieldless objects

Author: rafaqz

src/optics.jl

@@ -269,7 +269,7 @@ function mapproperties(f, obj::O, handler=Construct(), itr=nothing) where O
     # TODO move this helper elsewhere?
     pnames = propertynames(obj)
     if isempty(pnames)
-        return obj
+        return _maybeitr(obj, itr)
     else
         # TODO: this is too slow
         new_props, itr = reduce(pnames; init=((), itr)) do (vals, itr), p
@@ -334,7 +334,7 @@ $EXPERIMENTAL
     fnames = fieldnames(O)
     ctr = _constructor(H(), O)
     if isempty(fnames)
-        :(return obj)
+        :(return _maybeitr(obj, itr))
     else
         prop_args = map(fn -> :(getfield(obj, $(QuoteNode(fn)))), fnames)
         prop_exp = Expr(:tuple, prop_args...)

test/test_queries.jl

@@ -1,6 +1,6 @@
 using Accessors, Test, BenchmarkTools
 
-obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), (x=6.0,), )
+obj = (7, (a=17.0, b=2.0f0), ("3", 4, 5.0), (x=6.0,), [1])
 vals = (1.0, 2.0, 3.0, 4.0)
 
 # Fields is the default
@@ -24,7 +24,7 @@ println("set")
 @btime Accessors.set($obj, $slowlens, $vals)
 @test Accessors.set(obj, lens, vals) == 
     Accessors.set(obj, lens, vals) == 
-    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), (x=2.0,), )
+    (7, (a=1.0, b=2.0f0), ("3", 4, 5.0), (x=2.0,), [1])
 
 # using ProfileView
 # @profview for i in 1:1000000 Accessors.set(obj, lens, vals) end