fix(core): preserve asm-op mappings in MastForest::merge

CHANGELOG.md

@@ -22,6 +22,7 @@
 #### Fixes
 
 - Fixed stale `ReplayProcessor` doc comment links to `ExecutionTracer` after module-structure refactors.
+- Preserved `AssemblyOp` source mappings when merging `MastForest`s, preventing source-location loss after node deduplication.
 
 ## 0.22.0 (2025-03-18)
 

core/src/mast/debuginfo/asm_op_storage.rs

@@ -88,6 +88,11 @@ impl OpToAsmOpId {
         self.inner.num_elements()
     }
 
+    /// Returns all sparse `(op_idx, asm_op_id)` entries for a node, if the node exists.
+    pub fn asm_ops_for_node(&self, node_id: MastNodeId) -> Option<&[(usize, AsmOpId)]> {
+        self.inner.row(node_id)
+    }
+
     /// Registers AssemblyOps for a node's operations.
     ///
     /// `asm_ops` is a list of `(op_idx, asm_op_id)` pairs. The `op_idx` values must be strictly

core/src/mast/debuginfo/mod.rs

@@ -363,6 +363,11 @@ impl DebugInfo {
         self.asm_ops.get(asm_op_id)
     }
 
+    /// Returns all sparse `(op_idx, asm_op_id)` entries registered for a node.
+    pub fn asm_ops_for_node(&self, node_id: MastNodeId) -> Option<&[(usize, AsmOpId)]> {
+        self.asm_op_storage.asm_ops_for_node(node_id)
+    }
+
     // ASSEMBLY OP MUTATORS
     // --------------------------------------------------------------------------------------------