diff --git a/src/types.h b/src/types.h
index 2774b45..ebbed3f 100644
--- a/src/types.h
+++ b/src/types.h
@@ -83,7 +83,7 @@ typedef struct GroundError {
 typedef struct GroundValue {
     GroundValueType type;
     struct GroundStruct* customType;
-    union {
+    struct {
         int64_t intVal;
         double doubleVal;
         char* stringVal;