diff --git a/ffcx_backends/cpp.py b/ffcx_backends/cpp.py
index 1631ae4..a717ac9 100644
--- a/ffcx_backends/cpp.py
+++ b/ffcx_backends/cpp.py
@@ -420,7 +420,8 @@ class {factory_name}
     }}
 
     // Data
-    static inline const std::vector<int> enabled_coefficients{enabled_coefficients_init};
+    static constexpr std::array<int, {num_enabled_coefficients}>
+        enabled_coefficients = {enabled_coefficients_init};
     static constexpr bool needs_facet_permutations = {needs_facet_permutations};
 }};
 
@@ -458,6 +459,7 @@ def generator(
         code["name"] = ir.expression.name
 
         vals = ", ".join("1" if i else "0" for i in ir.enabled_coefficients)
+        code["num_enabled_coefficients"] = str(len(ir.enabled_coefficients))
         code["enabled_coefficients"] = f"{{{vals}}}"
         code["needs_facet_permutations"] = (
             "true" if ir.expression.needs_facet_permutations else "false"
@@ -469,6 +471,7 @@ def generator(
         implementation = integral.factory.format(
             factory_name=factory_name,
             enabled_coefficients_init=code["enabled_coefficients"],
+            num_enabled_coefficients=code["num_enabled_coefficients"],
             tabulate_tensor=code["tabulate_tensor"],
             needs_facet_permutations=code["needs_facet_permutations"],
             scalar_type=options["scalar_type"],
diff --git a/test/test_cpp.py b/test/test_cpp.py
index 1215776..e137726 100644
--- a/test/test_cpp.py
+++ b/test/test_cpp.py
@@ -15,8 +15,9 @@ def test_integral() -> None:
     domain = ufl.Mesh(basix.ufl.element("Lagrange", "triangle", 1, shape=(2,)))
     space = ufl.FunctionSpace(domain, element)
     u, v = ufl.TrialFunction(space), ufl.TestFunction(space)
+    f = ufl.Coefficient(space)
 
-    a = (ufl.inner(u, v) + ufl.inner(ufl.grad(u), ufl.grad(v))) * ufl.dx
+    a = (ufl.inner(u, v) + f * ufl.inner(ufl.grad(u), ufl.grad(v))) * ufl.dx
     opts = get_options({"language": "ffcx_backends.cpp"})
 
     compiled_objects = compile_ufl_objects([a], opts)