diff --git a/src/libotutil/ot-variant-builder.c b/src/libotutil/ot-variant-builder.c
index 92ac8ede..754b9323 100644
--- a/src/libotutil/ot-variant-builder.c
+++ b/src/libotutil/ot-variant-builder.c
@@ -760,10 +760,10 @@ ot_variant_builder_info_new (OtVariantBuilder *builder, const GVariantType *type
 {
   OtVariantBuilderInfo *info;
 
-  info = (OtVariantBuilderInfo *) g_slice_new0 (OtVariantBuilderInfo);
-
   g_return_val_if_fail (g_variant_type_is_container (type), NULL);
 
+  info = (OtVariantBuilderInfo *) g_slice_new0 (OtVariantBuilderInfo);
+
   info->builder = builder;
   info->type = g_variant_type_copy (type);
   info->type_info = g_variant_type_info_get (type);
@@ -845,10 +845,10 @@ ot_variant_builder_new (const GVariantType *type,
 {
   OtVariantBuilder *builder;
 
-  builder = (OtVariantBuilder *) g_slice_new0 (OtVariantBuilder);
-
   g_return_val_if_fail (g_variant_type_is_container (type), NULL);
 
+  builder = (OtVariantBuilder *) g_slice_new0 (OtVariantBuilder);
+
   builder->head = ot_variant_builder_info_new (builder, type);
   builder->ref_count = 1;
   builder->fd = fd;