diff --git a/packages/babel-plugin-minify-mangle-names/src/index.js b/packages/babel-plugin-minify-mangle-names/src/index.js
index 808dab05b..a292b668c 100644
--- a/packages/babel-plugin-minify-mangle-names/src/index.js
+++ b/packages/babel-plugin-minify-mangle-names/src/index.js
@@ -29,7 +29,6 @@ module.exports = ({ types: t, traverse }) => {
       this.eval = _eval;
       this.reuse = reuse;
 
-      this.unsafeScopes = new Set;
       this.visitedScopes = new Set;
 
       this.tracker = new Tracker({ reuse });
@@ -51,13 +50,6 @@ module.exports = ({ types: t, traverse }) => {
       return hop.call(this.blacklist, name) && this.blacklist[name];
     }
 
-    markUnsafeScopes(scope) {
-      let evalScope = scope;
-      do {
-        this.unsafeScopes.add(evalScope);
-      } while (evalScope = evalScope.parent);
-    }
-
     crawlScope() {
       traverse.clearCache();
       this.program.scope.crawl();