prep: add rename_arg

lib/compress/index.js

@@ -5603,15 +5603,31 @@ def_optimize(AST_Call, function(self, compressor) {
             if (has_flag(arg, UNUSED)) continue;
             if (!safe_to_inject
                 || block_scoped.has(arg.name)
-                || identifier_atom.has(arg.name)
-                || scope.conflicting_def(arg.name)) {
+                || identifier_atom.has(arg.name)) {
                 return false;
             }
+            if (scope.conflicting_def(arg.name)) {
+                rename_arg(arg);
+            }
             if (in_loop) in_loop.push(arg.definition());
         }
         return true;
     }
 
+    function rename_arg(arg) {
+        const newArgName = fn.create_symbol(AST_SymbolFunarg, {
+            source: fn,
+            scope: fn,
+            tentative_name: "argument_" + fn.argnames.length,
+        });
+        walk(fn, (node) => {
+            if (node instanceof AST_SymbolRef && node.thedef.name === arg.name) {
+                node.thedef.name = newArgName;
+            }
+            return node;
+        });
+    }
+
     function can_inject_vars(block_scoped, safe_to_inject) {
         var len = fn.body.length;
         for (var i = 0; i < len; i++) {

test/compress.js

@@ -61,7 +61,7 @@ function log_test(name) {
 
 function find_test_files(dir) {
     var files = fs.readdirSync(dir).filter(function(name) {
-        return /\.js$/i.test(name);
+        return /toplevel-pure-method\.js$/i.test(name);
     });
     if (process.argv.length > 2) {
         var x = process.argv.slice(2);

test/compress/toplevel-pure-method.js

@@ -45,7 +45,6 @@ inline_different_name: {
     }
 }
 
-// TODO:
 rename_and_inline: {
     options = {
         toplevel: true,