From 298bd60e61579381fc167636727a50ff6d891599 Mon Sep 17 00:00:00 2001
From: leafstark <695549485@qq.com>
Date: Thu, 21 Oct 2021 21:27:32 +0800
Subject: [PATCH] fix: add Non-empty judgment

---
 src/reference-tracker.js | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/reference-tracker.js b/src/reference-tracker.js
index faa7130..e1a850e 100644
--- a/src/reference-tracker.js
+++ b/src/reference-tracker.js
@@ -394,23 +394,28 @@ export class ReferenceTracker {
                     info: nextTraceMap[READ],
                 }
             }
-            yield* this._iterateVariableReferences(
-                findVariable(this.globalScope, specifierNode.local),
-                path,
-                nextTraceMap,
-                false,
-            )
-
+            const variable = findVariable(this.globalScope, specifierNode.local)
+            if (variable != null) {
+                yield* this._iterateVariableReferences(
+                    variable,
+                    path,
+                    nextTraceMap,
+                    false,
+                )
+            }
             return
         }
 
         if (type === "ImportNamespaceSpecifier") {
-            yield* this._iterateVariableReferences(
-                findVariable(this.globalScope, specifierNode.local),
-                path,
-                traceMap,
-                false,
-            )
+            const variable = findVariable(this.globalScope, specifierNode.local)
+            if (variable != null) {
+                yield* this._iterateVariableReferences(
+                    findVariable(this.globalScope, specifierNode.local),
+                    path,
+                    traceMap,
+                    false,
+                )
+            }
             return
         }