diff --git a/src/hooks/__tests__/instrument.test.ts b/src/hooks/__tests__/instrument.test.ts
index 456b1aea..5032399d 100644
--- a/src/hooks/__tests__/instrument.test.ts
+++ b/src/hooks/__tests__/instrument.test.ts
@@ -175,29 +175,29 @@ describe(instrument.transform, () => {
         },
       ];
 
-      const outer = (...args) => global.AppMapRecordHook.call(
+      const outer = (...$appmap$args) => global.AppMapRecordHook.call(
         undefined,
         (arg) => arg + 42,
-        args,
+        $appmap$args,
         __appmapFunctionRegistry[0],
       );
 
-      export const testFun = (...args) =>
+      export const testFun = (...$appmap$args) =>
         global.AppMapRecordHook.call(
           undefined,
           (arg) => {
             var s42 = y => y - 42;
             let s43 = y => y - 43;
-            const inner = (...args) =>
+            const inner = (...$appmap$args) =>
               global.AppMapRecordHook.call(
                 undefined,
                 (x) => s42(x) * 2,
-                args,
+                $appmap$args,
                 __appmapFunctionRegistry[1],
               );
             return inner(arg);
           },
-          args,
+          $appmap$args,
           __appmapFunctionRegistry[2],
         );
     `,
@@ -255,20 +255,20 @@ describe(instrument.transform, () => {
         },
       ];
 
-      exports.testFun = (...args) =>
+      exports.testFun = (...$appmap$args) =>
         global.AppMapRecordHook.call(
           undefined,
           (arg) => {
-            const inner = (...args) =>
+            const inner = (...$appmap$args) =>
               global.AppMapRecordHook.call(
                 undefined,
                 (x) => x * 2,
-                args,
+                $appmap$args,
                 __appmapFunctionRegistry[0],
               );
             return inner(arg);
           },
-          args,
+          $appmap$args,
           __appmapFunctionRegistry[1],
         );
     `,
@@ -304,8 +304,8 @@ describe(instrument.transform, () => {
           "static": true
         }];
 
-        const testFun = (...args) => global.AppMapRecordHook.call(undefined, x => x * 2,
-          args, __appmapFunctionRegistry[0]);
+        const testFun = (...$appmap$args) => global.AppMapRecordHook.call(undefined, x => x * 2,
+          $appmap$args, __appmapFunctionRegistry[0]);
 
         exports.testFun = testFun;
       `,
diff --git a/src/hooks/instrument.ts b/src/hooks/instrument.ts
index dabba530..c6c68e3b 100644
--- a/src/hooks/instrument.ts
+++ b/src/hooks/instrument.ts
@@ -176,7 +176,7 @@ function wrapLambda(
   lambda: ESTree.ArrowFunctionExpression,
   functionInfo: FunctionInfo,
 ): ESTree.ArrowFunctionExpression {
-  const args = identifier("args");
+  const args = identifier("$appmap$args");
   return {
     type: "ArrowFunctionExpression",
     async: lambda.async,
diff --git a/test/__snapshots__/simple.test.ts.snap b/test/__snapshots__/simple.test.ts.snap
index 00d03c66..b960e3c0 100644
--- a/test/__snapshots__/simple.test.ts.snap
+++ b/test/__snapshots__/simple.test.ts.snap
@@ -285,26 +285,38 @@ exports[`mapping a simple script 1`] = `
         {
           "children": [
             {
-              "location": "index.js:15",
+              "location": "index.js:10",
+              "name": "promised",
+              "static": true,
+              "type": "function",
+            },
+            {
+              "location": "index.js:16",
               "name": "immediatePromise",
               "static": true,
               "type": "function",
             },
             {
-              "location": "index.js:19",
+              "location": "index.js:20",
               "name": "throws",
               "static": true,
               "type": "function",
             },
             {
-              "location": "index.js:4",
-              "name": "foo",
+              "location": "index.js:29",
+              "name": "argsInClosure",
               "static": true,
               "type": "function",
             },
             {
-              "location": "index.js:9",
-              "name": "promised",
+              "location": "index.js:34",
+              "name": "incr",
+              "static": true,
+              "type": "function",
+            },
+            {
+              "location": "index.js:5",
+              "name": "foo",
               "static": true,
               "type": "function",
             },
@@ -355,7 +367,7 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 1,
-      "lineno": 19,
+      "lineno": 20,
       "method_id": "throws",
       "parameters": [],
       "path": "index.js",
@@ -380,7 +392,7 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 3,
-      "lineno": 4,
+      "lineno": 5,
       "method_id": "foo",
       "parameters": [
         {
@@ -408,7 +420,7 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 5,
-      "lineno": 4,
+      "lineno": 5,
       "method_id": "foo",
       "parameters": [
         {
@@ -436,7 +448,7 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 7,
-      "lineno": 9,
+      "lineno": 10,
       "method_id": "promised",
       "parameters": [],
       "path": "index.js",
@@ -459,7 +471,7 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 9,
-      "lineno": 9,
+      "lineno": 10,
       "method_id": "promised",
       "parameters": [
         {
@@ -488,7 +500,7 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 11,
-      "lineno": 15,
+      "lineno": 16,
       "method_id": "immediatePromise",
       "parameters": [],
       "path": "index.js",
@@ -511,7 +523,69 @@ exports[`mapping a simple script 1`] = `
       "defined_class": "index",
       "event": "call",
       "id": 13,
-      "lineno": 19,
+      "lineno": 29,
+      "method_id": "argsInClosure",
+      "parameters": [],
+      "path": "index.js",
+      "static": true,
+      "thread_id": 0,
+    },
+    {
+      "defined_class": "index",
+      "event": "call",
+      "id": 14,
+      "lineno": 34,
+      "method_id": "incr",
+      "parameters": [],
+      "path": "index.js",
+      "static": true,
+      "thread_id": 0,
+    },
+    {
+      "elapsed": 31.337,
+      "event": "return",
+      "id": 15,
+      "parent_id": 14,
+      "return_value": {
+        "class": "Number",
+        "value": "0",
+      },
+      "thread_id": 0,
+    },
+    {
+      "defined_class": "index",
+      "event": "call",
+      "id": 16,
+      "lineno": 34,
+      "method_id": "incr",
+      "parameters": [],
+      "path": "index.js",
+      "static": true,
+      "thread_id": 0,
+    },
+    {
+      "elapsed": 31.337,
+      "event": "return",
+      "id": 17,
+      "parent_id": 16,
+      "return_value": {
+        "class": "Number",
+        "value": "1",
+      },
+      "thread_id": 0,
+    },
+    {
+      "elapsed": 31.337,
+      "event": "return",
+      "id": 18,
+      "parent_id": 13,
+      "thread_id": 0,
+    },
+    {
+      "defined_class": "index",
+      "event": "call",
+      "id": 19,
+      "lineno": 20,
       "method_id": "throws",
       "parameters": [],
       "path": "index.js",
@@ -528,8 +602,8 @@ exports[`mapping a simple script 1`] = `
           "object_id": 5,
         },
       ],
-      "id": 14,
-      "parent_id": 13,
+      "id": 20,
+      "parent_id": 19,
       "thread_id": 0,
     },
   ],
diff --git a/test/simple/index.js b/test/simple/index.js
index a8612bd8..d800b329 100644
--- a/test/simple/index.js
+++ b/test/simple/index.js
@@ -1,4 +1,5 @@
 /* eslint-disable @typescript-eslint/no-var-requires */
+const assert = require("assert");
 const { setTimeout } = require("timers/promises");
 
 function foo(x) {
@@ -25,6 +26,18 @@ function skipped() {
   console.log("skipped");
 }
 
+function argsInClosure() {
+  // make sure "args" local is not shadowed by the instrumentation
+
+  let args = 0;
+
+  const incr = () => args++;
+
+  incr();
+  incr();
+  assert.equal(args, 2);
+}
+
 try {
   throws();
   console.log(foo(43));
@@ -36,3 +49,4 @@ console.log(foo(42));
 promised().then(console.log);
 promised(false).catch(console.log);
 immediatePromise().then(console.log);
+argsInClosure();