handle negated constants correctly in collapse_vars (#2975)

fixes #2974
2018-03-06 00:45:58 +08:00
parent 951d87ca94
commit fe51a91395
2 changed files with 37 additions and 2 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -778,8 +778,7 @@ merge(Compressor.prototype, {
                lhs = lhs.fixed_value();
            }
            if (!lhs) return true;
-            if (lhs instanceof AST_RegExp) return false;
-            if (lhs instanceof AST_Constant) return true;
+            if (lhs.is_constant()) return true;
            return is_lhs_read_only(lhs);
        }
        return false;