diff --git a/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-end-detached-prototype.js b/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-end-detached-prototype.js
new file mode 100644
index 0000000000..02bb02afd8
--- /dev/null
+++ b/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-end-detached-prototype.js
@@ -0,0 +1,42 @@
+// Copyright (C) 2019 Google. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.copywithin
+description: >
+  SECURITY: end argument is coerced to an integer values
+  causing array detachment, but the value is still defined
+  by a prototype
+info: |
+  22.2.3.5%TypedArray%.prototype.copyWithin ( target, start [ , end ] )
+  ...
+  8. If end is undefined, let relativeEnd be len; else let relativeEnd be ? ToInteger(end).
+  ... 
+  10. Let count be min(final - from, len - to).
+  11. If count > 0, then
+    a. NOTE: The copying must be performed in a manner that preserves the bit-level encoding of the source data.
+    b. Let buffer be O.[[ViewedArrayBuffer]].
+    c. If IsDetachedBuffer(buffer) is true, throw a TypeError exception. 
+  ...
+includes: [testTypedArray.js, detachArrayBuffer.js]
+features: [TypedArray]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  
+  var ta;
+  var array = [];
+
+  function detachAndReturnIndex(){
+      $DETACHBUFFER(ta.buffer);
+      Object.setPrototypeOf(ta, array);
+      return 101;
+  }
+
+  array.length = 10000; // big arrays are more likely to cause a crash if they are accessed after they are freed
+  array.fill(7, 0);
+  ta = new TA(array);
+  assert.throws(TypeError, function(){ 
+    ta.copyWithin(0, 100, {valueOf : detachAndReturnIndex}); },
+  "should throw TypeError as array is detached");
+  
+});
diff --git a/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-end-detached.js b/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-end-detached.js
new file mode 100644
index 0000000000..188fafa654
--- /dev/null
+++ b/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-end-detached.js
@@ -0,0 +1,39 @@
+// Copyright (C) 2019 Google. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.copywithin
+description: >
+  SECURITY: end argument is coerced to an integer values
+  causing array detachment
+info: |
+  22.2.3.5 %TypedArray%.prototype.copyWithin ( target, start [ , end ] )
+
+  ...
+  8. If end is undefined, let relativeEnd be len; else let relativeEnd be ? ToInteger(end).
+  ...
+  10. Let count be min(final - from, len - to).
+  11. If count > 0, then
+    a. NOTE: The copying must be performed in a manner that preserves the bit-level encoding of the source data.
+    b. Let buffer be O.[[ViewedArrayBuffer]].
+    c. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+  ...
+includes: [testTypedArray.js, detachArrayBuffer.js]
+features: [TypedArray]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  
+  var ta;
+  function detachAndReturnIndex(){
+      $DETACHBUFFER(ta.buffer);
+      return 900;
+  }
+
+  var array = [];
+  array.length = 10000; // big arrays are more likely to cause a crash if they are accessed after they are freed
+  array.fill(7, 0);
+  ta = new TA(array);
+  assert.throws(TypeError, function(){ 
+    ta.copyWithin(0, 100, {valueOf : detachAndReturnIndex});
+  "should throw TypeError as array is detached");
+});
diff --git a/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-start-detached.js b/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-start-detached.js
new file mode 100644
index 0000000000..d838de8575
--- /dev/null
+++ b/test/built-ins/TypedArray/prototype/copyWithin/coerced-values-start-detached.js
@@ -0,0 +1,41 @@
+// Copyright (C) 2019 Google. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.copywithin
+description: >
+  SECURITY: start argument is coerced to an integer value, which detached
+  the array
+info: |
+  22.2.3.5 %TypedArray%.prototype.copyWithin ( target, start [ , end ] )
+
+  ...
+  6. Let relativeStart be ? ToInteger(start).
+  ...
+  10. Let count be min(final - from, len - to).
+  11. If count > 0, then
+    a. NOTE: The copying must be performed in a manner that preserves the bit-level encoding of the source data.
+    b. Let buffer be O.[[ViewedArrayBuffer]].
+    c. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+  ...
+includes: [testTypedArray.js, detachArrayBuffer.js]
+features: [TypedArray]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  
+  var ta;
+  function detachAndReturnIndex(){
+      $DETACHBUFFER(ta.buffer);
+      return 100;
+  }
+
+  var array = [];
+  array.length = 10000; // big arrays are more likely to cause a crash if they are accessed after they are freed
+  array.fill(7, 0);
+  ta = new TA(array);
+  assert.throws(TypeError, function(){ 
+    ta.copyWithin(0, {valueOf : detachAndReturnIndex}, 1000);
+    "should throw TypeError as array is detached");
+  
+  });
+});