diff --git a/gnu/packages/maths.scm b/gnu/packages/maths.scm
index 15c020e6c4..98bae9ecb5 100644
--- a/gnu/packages/maths.scm
+++ b/gnu/packages/maths.scm
@@ -6811,7 +6811,7 @@ (define-public dune-alugrid
                   "doc/dune-grid/grids/gridfactory/testgrids"))
                #t))
            (add-after 'build 'build-tests
-             (lambda* (#:key make-flags parallel-build? #:allow-other-keys)
+             (lambda* (#:key inputs make-flags parallel-build? #:allow-other-keys)
                (setenv "CPLUS_INCLUDE_PATH"
                        (string-append (assoc-ref inputs "dune-grid") "/share"))
                (apply invoke "make" "build_tests"