diff --git a/build-aux/hydra/gnu-system.scm b/build-aux/hydra/gnu-system.scm
index e5326c4bbd..62eb957f83 100644
--- a/build-aux/hydra/gnu-system.scm
+++ b/build-aux/hydra/gnu-system.scm
@@ -24,7 +24,7 @@
 
 (use-modules (system base compile))
 
-(eval-when (compile load eval)
+(eval-when (expand load eval)
 
   ;; Pre-load the compiler so we don't end up auto-compiling it.
   (compile #t)
diff --git a/build-aux/hydra/guix.scm b/build-aux/hydra/guix.scm
index 659b8bfbc1..08193ec82e 100644
--- a/build-aux/hydra/guix.scm
+++ b/build-aux/hydra/guix.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -22,7 +22,7 @@
 ;;;
 
 ;; Attempt to use our very own Guix modules.
-(eval-when (compile load eval)
+(eval-when (expand load eval)
 
   ;; Ignore any available .go, and force recompilation.  This is because our
   ;; checkout in the store has mtime set to the epoch, and thus .go files look