diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index cca0ad991b..7f3d3b9db8 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -452,10 +452,10 @@ (define lines
           ;; but it also truncates values anyway, so don't try to support it.
           (let ((index (string-index line #\=)))
             (if index
-                (vhash-cons (string-take line index)
+                (vhash-cons (pk 'variable line (string-take line index))
                             (string-drop line (+ 1 index))
                             table)
-                table)))
+                (pk 'dropped line table))))
         vlist-null
         lines))