diff --git a/Project.toml b/Project.toml
index 6ba21563..cb8c6950 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "HerbSearch"
 uuid = "3008d8e8-f9aa-438a-92ed-26e9c7b4829f"
 authors = ["Sebastijan Dumancic <s.dumancic@tudelft.nl>", "Jaap de Jong <J.deJong-18@student.tudelft.nl>", "Nicolae Filat <N.Filat@student.tudelft.nl>", "Piotr Cichoń <gitlab@gitlab.ewi.tudelft.nl>", "Tilman Hinnerichs <t.r.hinnerichs@tudelft.nl>"]
-version = "0.4.1"
+version = "0.4.2"
 
 [deps]
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
diff --git a/src/program_iterator.jl b/src/program_iterator.jl
index fb5fcbd9..d70f65df 100644
--- a/src/program_iterator.jl
+++ b/src/program_iterator.jl
@@ -71,7 +71,7 @@ function generate_iterator(mod::Module, ex::Expr, mut::Bool=false)
     @match ex begin
         Expr(:(<:), decl::Expr, super) => begin            
             # a check that `super` is a subtype of `ProgramIterator`
-            check = :(eval($mod.$super) <: HerbSearch.ProgramIterator || 
+            check = :($mod.$super <: HerbSearch.ProgramIterator || 
                 throw(ArgumentError("attempting to inherit a non-ProgramIterator")))
             
             # process the decl 
diff --git a/test/Project.toml b/test/Project.toml
index 9e172f7b..7714cc39 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -4,7 +4,6 @@ HerbConstraints = "1fa96474-3206-4513-b4fa-23913f296dfc"
 HerbCore = "2b23ba43-8213-43cb-b5ea-38c12b45bd45"
 HerbGrammar = "4ef9e186-2fe5-4b24-8de7-9f7291f24af7"
 HerbInterpret = "5bbddadd-02c5-4713-84b8-97364418cca7"
-HerbSearch = "3008d8e8-f9aa-438a-92ed-26e9c7b4829f"
 HerbSpecification = "6d54aada-062f-46d8-85cf-a1ceaf058a06"
 LegibleLambdas = "f1f30506-32fe-5131-bd72-7c197988f9e5"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
diff --git a/test/test_programiterator_macro.jl b/test/test_programiterator_macro.jl
index 29a2377c..4d3c1330 100644
--- a/test/test_programiterator_macro.jl
+++ b/test/test_programiterator_macro.jl
@@ -36,6 +36,18 @@
         @test it.f1 && it.f2 == 4
     end
 
+    @testset "inheriting from something !<: ProgramIterator" begin
+        @test_throws ArgumentError @programiterator ConcreteIterator(
+            f1::Bool,
+            f2
+        ) <: AbstractFloat
+
+        # it = ConcreteIterator(g, s, max_depth = max_depth, max_size = max_size, true, 4)
+
+        # @test ConcreteIterator <: IteratorFamily
+        # @test it.f1 && it.f2 == 4
+    end
+
     @testset "mutable iterator" begin
         @programiterator mutable AnotherIterator() <: IteratorFamily