diff --git a/src/main/java/org/jcnc/snow/compiler/ir/builder/ProgramBuilder.java b/src/main/java/org/jcnc/snow/compiler/ir/builder/ProgramBuilder.java
index 6331d57..9b823fb 100644
--- a/src/main/java/org/jcnc/snow/compiler/ir/builder/ProgramBuilder.java
+++ b/src/main/java/org/jcnc/snow/compiler/ir/builder/ProgramBuilder.java
@@ -31,17 +31,17 @@ public final class ProgramBuilder {
     public IRProgram buildProgram(List<Node> roots) {
         IRProgram prog = new IRProgram();
         for (Node n : roots) {
-            if (n instanceof ModuleNode m) {
-                // 模块节点：将模块内的所有函数加入程序
-                m.functions().forEach(f -> prog.add(buildFunction(f)));
-            } else if (n instanceof FunctionNode f) {
-                // 顶层函数节点
-                prog.add(buildFunction(f));
-            } else if (n instanceof StatementNode s) {
-                // 顶层脚本语句，包装为 _start 函数
-                prog.add(buildFunction(wrapTopLevel(s)));
-            } else {
-                throw new IllegalStateException("Unsupported top-level node: " + n);
+            switch (n) {
+                case ModuleNode m ->
+                    // 模块节点：将模块内的所有函数加入程序
+                        m.functions().forEach(f -> prog.add(buildFunction(f)));
+                case FunctionNode f ->
+                    // 顶层函数节点
+                        prog.add(buildFunction(f));
+                case StatementNode s ->
+                    // 顶层脚本语句，包装为 _start 函数
+                        prog.add(buildFunction(wrapTopLevel(s)));
+                case null, default -> throw new IllegalStateException("Unsupported top-level node: " + n);
             }
         }
         return prog;