fix corner case in `reduce_vars` (#4665)

fixes #4664

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/compress.js b/lib/compress.js
index a58e2816..325c0cd0 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -757,7 +757,9 @@ merge(Compressor.prototype, {
                 var value = iife.args[i];
                 scan_declaration(tw, compressor, arg, function() {
                     var j = fn.argnames.indexOf(arg);
-                    return (j < 0 ? value : iife.args[j]) || make_node(AST_Undefined, iife);
+                    var arg = j < 0 ? value : iife.args[j];
+                    if (arg instanceof AST_Sequence && arg.expressions.length < 2) arg = arg.expressions[0];
+                    return arg || make_node(AST_Undefined, iife);
                 }, visit);
             });
             if (fn.rest) scan_declaration(tw, compressor, fn.rest, compressor.option("rests") && function() {
@@ -3644,7 +3646,7 @@ merge(Compressor.prototype, {
     // methods to determine if an expression has a numeric result type
     (function(def) {
         def(AST_Node, return_false);
-        var binary = makePredicate("- * / % & | ^ << >> >>>");
+        var binary = makePredicate("- * / % ** & | ^ << >> >>>");
         def(AST_Assign, function(compressor) {
             return binary[this.operator.slice(0, -1)]
                 || this.operator == "=" && this.right.is_number(compressor);