feat(joinir): Phase 227 - CarrierRole separation (LoopState vs ConditionOnly)

- Add CarrierRole enum to distinguish state carriers from condition-only carriers
- ConditionOnly carriers (is_digit_pos) skip exit PHI but keep header PHI
- Update all test struct literals with role field
- 877/884 tests PASS (7 pre-existing failures unrelated)

Remaining: ValueId(0) undefined - header PHI initialization for ConditionOnly

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/mir/builder/control_flow/joinir/patterns/common_init.rs

@@ -162,6 +162,7 @@ impl CommonPatternInitializer {
                             name: name.clone(),
                             host_id: ValueId(0),  // Dummy
                             join_id: None,
+                            role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState, // Phase 227: Default
                         })
                     } else {
                         None

src/mir/builder/control_flow/joinir/patterns/exit_binding.rs

@@ -142,6 +142,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -181,11 +182,13 @@ mod tests {
                     name: "printed".to_string(),
                     host_id: ValueId(11),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
                 CarrierVar {
                     name: "sum".to_string(),
                     host_id: ValueId(10),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
             ],
         );
@@ -228,6 +231,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -256,6 +260,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -284,6 +289,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -315,6 +321,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 

src/mir/builder/control_flow/joinir/patterns/exit_binding_applicator.rs

@@ -52,6 +52,7 @@ pub fn apply_exit_bindings_to_boundary(
             carrier_name: carrier.name.clone(),
             host_slot: post_loop_id,
             join_exit_value: join_exit_id,
+            role: carrier.role, // Phase 227: Propagate role from CarrierInfo
         });
 
         join_outputs.push(join_exit_id);
@@ -83,10 +84,12 @@ pub fn apply_exit_bindings_to_boundary(
 ///
 /// LoopExitBinding for the loop variable
 pub fn create_loop_var_exit_binding(carrier_info: &CarrierInfo) -> LoopExitBinding {
+    use crate::mir::join_ir::lowering::carrier_info::CarrierRole;
     LoopExitBinding {
         carrier_name: carrier_info.loop_var_name.clone(),
         join_exit_value: carrier_info.loop_var_id, // Loop var maps to itself
         host_slot: carrier_info.loop_var_id,
+        role: CarrierRole::LoopState, // Phase 227: Loop var is always LoopState
     }
 }
 
@@ -104,6 +107,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 

src/mir/builder/control_flow/joinir/patterns/exit_binding_constructor.rs

@@ -40,6 +40,7 @@ pub fn build_loop_exit_bindings(
             carrier_name: carrier.name.clone(),
             join_exit_value: join_exit_id,
             host_slot: carrier.host_id,
+            role: carrier.role, // Phase 227: Propagate role from CarrierInfo
         });
 
         // Allocate new ValueId for post-loop carrier value
@@ -90,6 +91,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -127,11 +129,13 @@ mod tests {
                     name: "printed".to_string(),
                     host_id: ValueId(11),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
                 CarrierVar {
                     name: "sum".to_string(),
                     host_id: ValueId(10),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
             ],
         );

src/mir/builder/control_flow/joinir/patterns/exit_binding_validator.rs

@@ -69,6 +69,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -88,11 +89,13 @@ mod tests {
                     name: "printed".to_string(),
                     host_id: ValueId(11),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
                 CarrierVar {
                     name: "sum".to_string(),
                     host_id: ValueId(10),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
             ],
         );
@@ -115,6 +118,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -135,6 +139,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 
@@ -155,6 +160,7 @@ mod tests {
                 name: "sum".to_string(),
                 host_id: ValueId(10),
                 join_id: None,
+                role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
             }],
         );
 

src/mir/builder/control_flow/joinir/patterns/pattern2_with_break.rs

@@ -475,9 +475,13 @@ impl MirBuilder {
         // Issue: CommonPatternInitializer includes all variables in variable_map as carriers,
         // but only variables with updates in the loop body are true carriers.
         // Condition-only variables (like 'len', 's') should be excluded.
+        //
+        // Phase 227: Keep ConditionOnly carriers even if they don't have updates
+        // (they're used in loop/break conditions, not updated)
         let original_carrier_count = carrier_info.carriers.len();
         carrier_info.carriers.retain(|carrier| {
-            carrier_updates.contains_key(&carrier.name)
+            use crate::mir::join_ir::lowering::carrier_info::CarrierRole;
+            carrier_updates.contains_key(&carrier.name) || carrier.role == CarrierRole::ConditionOnly
         });
 
         eprintln!(

src/mir/builder/control_flow/joinir/patterns/pattern4_carrier_analyzer.rs

@@ -276,16 +276,19 @@ mod tests {
                     name: "i".to_string(),
                     host_id: ValueId(1),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
                 CarrierVar {
                     name: "sum".to_string(),
                     host_id: ValueId(2),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
                 CarrierVar {
                     name: "M".to_string(),
                     host_id: ValueId(3),
                     join_id: None,
+                    role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                 },
             ],
             trim_helper: None,

src/mir/builder/control_flow/joinir/patterns/pattern_pipeline.rs

@@ -396,11 +396,13 @@ mod tests {
                         name: "sum".to_string(),
                         host_id: ValueId(10),
                         join_id: None,
+                        role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                     },
                     CarrierVar {
                         name: "count".to_string(),
                         host_id: ValueId(11),
                         join_id: None,
+                        role: crate::mir::join_ir::lowering::carrier_info::CarrierRole::LoopState,
                     },
                 ],
                 trim_helper: None,