1 files changed, 8 insertions, 1 deletions
diff --git a/lib/compress.js b/lib/compress.js
index d99310ed..7c1c3b42 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -595,7 +595,14 @@ merge(Compressor.prototype, {
             var expr = node.expression;
             if (!(expr instanceof AST_SymbolRef)) return;
             var def = expr.definition();
-            if (is_arguments(def) && node.property instanceof AST_Number) def.reassigned = true;
+            if (!is_arguments(def)) return;
+            var key = node.property;
+            if (key.is_constant()) key = key.value;
+            if (!(key instanceof AST_Node) && !/^[1-9]*[0-9]$/.test(key)) return;
+            def.reassigned = true;
+            (key instanceof AST_Node ? def.scope.argnames : [ def.scope.argnames[key] ]).forEach(function(argname) {
+                if (argname instanceof AST_SymbolFunarg) argname.definition().fixed = false;
+            });
         }
 
         function scan_declaration(tw, lhs, fixed, visit) {