ir done'ish

examples/50-smoke.sx

@@ -1782,6 +1782,24 @@ END;
         print("opt param 7: {}\n", opt_process(7));         // opt param 7: 7
     }
 
+    // Assignment to optional variable (f32 → ?f32)
+    {
+        iw: ?f32 = null;
+        w: f32 = 42.5;
+        iw = w;
+        print("opt reassign: {}\n", iw ?? 0.0);                // opt reassign: 42.5
+
+        // Assignment of computed value to optional
+        iw2: ?f32 = null;
+        a: ?f32 = 10.0;
+        if v := a { iw2 = v + 5.0; }
+        print("opt compute assign: {}\n", iw2 ?? 0.0);         // opt compute assign: 15.0
+
+        // Re-assign optional back to null
+        iw2 = null;
+        print("opt re-null: {}\n", iw2 ?? 99.0);               // opt re-null: 99.0
+    }
+
     // Generic function with ?T return
     {
         first_pos :: ($T: Type, a: T, b: T) -> ?T {