fix corner case in dead_code (#3969)

fixes #3967
2020-06-08 06:42:09 +01:00
parent 3230952d57
commit cd55eeb77c
2 changed files with 23 additions and 1 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3938,7 +3938,8 @@ merge(Compressor.prototype, {
        });
        def(AST_Binary, function(compressor) {
            return this.left.may_throw(compressor)
-                || this.right.may_throw(compressor);
+                || this.right.may_throw(compressor)
+                || this.operator == "in" && !is_object(this.right.tail_node());
        });
        def(AST_Block, function(compressor) {
            return any(this.body, compressor);