fix corner case in side_effects (#5299)

fixes #5298
2022-01-15 18:33:14 +00:00
parent dfd6418878
commit d96c59f9e6
2 changed files with 26 additions and 1 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -5541,7 +5541,9 @@ Compressor.prototype.compress = function(node) {
        });
        def(AST_ForEnumeration, function(compressor) {
            if (this.init.may_throw(compressor)) return true;
-            var obj = this.object.tail_node();
+            var obj = this.object;
+            if (obj.may_throw(compressor)) return true;
+            obj = obj.tail_node();
            if (!(obj instanceof AST_Array || obj.is_string(compressor))) return true;
            return this.body.may_throw(compressor);
        });