diff --git a/guix/lint.scm b/guix/lint.scm
index 38699e2927..1bebfe03d3 100644
--- a/guix/lint.scm
+++ b/guix/lint.scm
@@ -183,7 +183,7 @@
        (make-warning package
                      (G_ "name should be longer than a single character")
                      #:field 'name)))
-     ((string-match "_" name)
+     ((string-index name #\_)
       (list
        (make-warning package
                      (G_ "name should use hyphens instead of underscores")