diff --git a/compfib.zig b/compfib.zig
new file mode 100644
index 0000000..33c2c87
--- /dev/null
+++ b/compfib.zig
@@ -0,0 +1,12 @@
+const std = @import("std");
+const assert = std.debug.assert;
+
+fn fibonacci(x: u32) u32 {
+    if (x <= 1) return x;
+    return fibonacci(x - 1) + fibonacci(x - 2);
+}
+
+test "compile-time evaluation" {
+    var array: [fibonacci(6)]i32 = undefined;
+    assert(array.len == 8);
+}