diff --git a/tools/widl/typetree.c b/tools/widl/typetree.c
index 57a5736..961a3f1 100644
--- a/tools/widl/typetree.c
+++ b/tools/widl/typetree.c
@@ -102,7 +102,7 @@ type_t *type_new_basic(enum type_basic_type basic_type)
 
 type_t *type_new_int(enum type_basic_type basic_type, int sign)
 {
-    static type_t *int_types[TYPE_BASIC_INT_MAX][3];
+    static type_t *int_types[TYPE_BASIC_INT_MAX][3] = { { NULL } };
 
     assert(basic_type <= TYPE_BASIC_INT_MAX);