diff --git a/sharness.sh b/sharness.sh
index ec9cb01ab..3dc018439 100644
--- a/sharness.sh
+++ b/sharness.sh
@@ -21,7 +21,7 @@
 if test -n "${ZSH_VERSION-}"
 then
 	# shellcheck disable=SC2296
-	SHARNESS_SOURCE=${(%):-%x}
+	eval 'SHARNESS_SOURCE=${(%):-%x}'
 	emulate sh -o POSIX_ARGZERO
 else
 	# shellcheck disable=SC3028