diff --git a/mie/builder.c b/mie/builder.c
index c54e154..50861f9 100644
--- a/mie/builder.c
+++ b/mie/builder.c
@@ -79,8 +79,10 @@ void mie_ctx_destroy(struct mie_ctx *ctx)
 
 	const size_t nr_types = sizeof ctx->ctx_types / sizeof ctx->ctx_types[0];
 	for (size_t i = 0; i < nr_types; i++) {
-		mie_value_destroy(MIE_VALUE(ctx->ctx_types[i]));
-		ctx->ctx_types[i] = NULL;
+		if (ctx->ctx_types[i]) {
+			mie_value_destroy(MIE_VALUE(ctx->ctx_types[i]));
+			ctx->ctx_types[i] = NULL;
+		}
 	}
 
 	free(ctx);