diff --git a/interface/multifluid_mutant.cpp b/interface/multifluid_mutant.cpp
index 075e973b8ae43d9cd686aab3380bbf83f3d78266..f0b6484011dd9dca89a50983612bea6db413d9db 100644
--- a/interface/multifluid_mutant.cpp
+++ b/interface/multifluid_mutant.cpp
@@ -38,12 +38,7 @@ void add_multifluid_mutant_invariant(py::module& m) {
     m.def("build_multifluid_mutant_invariant", &build_multifluid_mutant_invariant<MultiFluid>);
 
     // Typedef for mutant with the invariant reducing function
-    using Mutant = std::invoke_result_t<decltype(build_multifluid_mutant_invariant<MultiFluid>), MultiFluid, nlohmann::json>;
-
-    // The reducing function type and the departure function types are the same
-    // as the base model
-    using RedType = std::decay_t<decltype(Mutant::redfunc)>;
-    using DepType = std::decay_t<decltype(MultiFluid::dep)>;
+    using Mutant = std::invoke_result_t<build_multifluid_mutant_invariant<MultiFluid>, MultiFluid, nlohmann::json>;
 
     // Define python wrapper of the mutant class
     auto wMutant = py::class_<Mutant>(m, "MultiFluidMutantInvariant")