fix: 对齐 ?? 与静态成员复合赋值的 counter/emitter 计数，并加 projected_pc 断言

crates/oxide_compiler/src/counter/expr/assignment.rs

@@ -13,10 +13,8 @@ impl Compiler {
             }
             self.count_expression(&member.object, ctx);
             self.count_expression(&assign.right, ctx);
-            if assign.operator != AssignmentOperator::Assign {
-                ctx.alloc_reg();
-                ctx.projected_pc += 1;
-            }
+            // Both plain (IC_SET_PROP) and compound (COMPOUND_MEMBER_*) emit one opcode + 3 ext
+            // words after the key load — no extra instruction for the compound case.
             ctx.count_load_const(); // key
             ctx.count_ic_set_with_ext(); // IC_SET_PROP or COMPOUND_MEMBER_* + 3 ext words
         } else if let oxide_parser::AssignmentTarget::ComputedMemberExpression(member) = &assign.left {

crates/oxide_compiler/src/counter/expr/control.rs

@@ -42,21 +42,27 @@ impl Compiler {
             self.count_expression(&log.right, ctx);
             ctx.alloc_reg();
             ctx.projected_pc += 1; // AND/OR
+        } else if matches!(log.operator, LogicalOperator::Coalesce) {
+            // Mirror emit_logical_expression's Coalesce path: it patches raw bytecode
+            // positions and does NOT consume a label id. Consuming one here would shift
+            // every later construct's label id and break resolve_label at emit time.
+            ctx.alloc_reg(); // dup register
+            ctx.projected_pc += 1; // LOAD_VAR (DUP)
+            ctx.projected_pc += 1; // JMP_IF_NULLISH
+            ctx.projected_pc += 1; // JMP over RHS on non-nullish
+            self.count_expression(&log.right, ctx);
+            ctx.projected_pc += 1; // LOAD_VAR (overwrite)
         } else {
             let id = ctx.next_label_id();
             ctx.alloc_reg(); // dup register
             ctx.projected_pc += 1; // LOAD_VAR (DUP)
-            ctx.projected_pc += 1; // JMP_IF_FALSE, JMP_IF_TRUE, or JMP_IF_NULLISH
-            if matches!(log.operator, LogicalOperator::Coalesce) {
-                ctx.projected_pc += 1; // JMP over RHS on non-nullish
-                ctx.labels.label_map.insert(Label::TernaryElse(id), ctx.projected_pc);
-            }
+            ctx.projected_pc += 1; // JMP_IF_FALSE or JMP_IF_TRUE
             self.count_expression(&log.right, ctx);
             ctx.projected_pc += 1; // LOAD_VAR (overwrite)
             let skip_label = match log.operator {
                 LogicalOperator::And => Label::TernaryEnd(id),
                 LogicalOperator::Or => Label::TernaryElse(id),
-                LogicalOperator::Coalesce => Label::TernaryEnd(id),
+                LogicalOperator::Coalesce => unreachable!("coalesce handled above"),
             };
             ctx.labels.label_map.insert(skip_label, ctx.projected_pc);
         }