diff --git a/src/mir/builder/calls/lowering.rs b/src/mir/builder/calls/lowering.rs
index e7c4612c..12cd7a64 100644
--- a/src/mir/builder/calls/lowering.rs
+++ b/src/mir/builder/calls/lowering.rs
@@ -7,6 +7,7 @@
 
 use crate::ast::ASTNode;
 use crate::mir::builder::{MirBuilder, MirType, MirInstruction};
+use crate::mir::{ValueId};
 use crate::mir::region::function_slot_registry::FunctionSlotRegistry;
 use super::function_lowering;
 use std::collections::HashMap;
@@ -267,16 +268,18 @@ impl MirBuilder {
         let mut slot_regs: Vec<(String, Option<MirType>)> = Vec::new();
 
         if let Some(ref mut f) = self.current_function {
-            // First parameter is always 'me'
-            let me_id = f.next_value_id();
+            // 📦 Hotfix 6: Use pre-reserved ValueIds instead of generating new ones
+            // MirFunction::new() already reserved ValueIds 0..N for parameters
+            // First parameter is always 'me' at ValueId(0)
+            let me_id = ValueId(0);
             f.params.push(me_id);
             self.variable_map.insert("me".to_string(), me_id);
             self.value_origin_newbox.insert(me_id, box_name.to_string());
             slot_regs.push(("me".to_string(), None));
 
-            // Then regular parameters
-            for p in params {
-                let pid = f.next_value_id();
+            // Then regular parameters at ValueId(1), ValueId(2), ...
+            for (idx, p) in params.iter().enumerate() {
+                let pid = ValueId((idx + 1) as u32);
                 f.params.push(pid);
                 self.variable_map.insert(p.clone(), pid);
                 slot_regs.push((p.clone(), None));