1 files changed, 1 insertions, 1 deletions
diff --git a/src/unit.c b/src/unit.c
index f7c0277..0a906fe 100644
--- a/src/unit.c
+++ b/src/unit.c
@@ -141,7 +141,7 @@ unit_convert_from(Unit *unit, const MPNumber *x, MPNumber *z)
 {
 g_return_val_if_fail(unit != NULL, FALSE);
 g_return_val_if_fail(x != NULL, FALSE);
- g_return_val_if_fail(x != NULL, FALSE);
+ g_return_val_if_fail(z != NULL, FALSE);
 
 if (unit->priv->from_function)
 return solve_function(unit->priv->from_function, x, z);