[errors] Improve NotGeneric error message

test/mjsunit/messages.js

Index: test/mjsunit/messages.js
diff --git a/test/mjsunit/messages.js b/test/mjsunit/messages.js
index 9c250048612946b54e103c6150f4a6060d16872a..ff91185a7270a6025302e8f8e44f912a262b74f5 100644
--- a/test/mjsunit/messages.js
+++ b/test/mjsunit/messages.js
@@ -192,33 +192,33 @@ test(function() {
 }, "this is not a Date object.", TypeError);
 
 // kNotGeneric
-test(function() {
-  String.prototype.toString.call(1);
-}, "String.prototype.toString is not generic", TypeError);
+test(() => String.prototype.toString.call(1),
+    "String.prototype.toString requires that 'this' be a String",
+    TypeError);
 
-test(function() {
-  String.prototype.valueOf.call(1);
-}, "String.prototype.valueOf is not generic", TypeError);
+test(() => String.prototype.valueOf.call(1),
+    "String.prototype.valueOf requires that 'this' be a String",
+    TypeError);
 
-test(function() {
-  Boolean.prototype.toString.call(1);
-}, "Boolean.prototype.toString is not generic", TypeError);
+test(() => Boolean.prototype.toString.call(1),
+    "Boolean.prototype.toString requires that 'this' be a Boolean",
+    TypeError);
 
-test(function() {
-  Boolean.prototype.valueOf.call(1);
-}, "Boolean.prototype.valueOf is not generic", TypeError);
+test(() => Boolean.prototype.valueOf.call(1),
+    "Boolean.prototype.valueOf requires that 'this' be a Boolean",
+    TypeError);
 
-test(function() {
-  Number.prototype.toString.call({});
-}, "Number.prototype.toString is not generic", TypeError);
+test(() => Number.prototype.toString.call({}),
+    "Number.prototype.toString requires that 'this' be a Number",
+    TypeError);
 
-test(function() {
-  Number.prototype.valueOf.call({});
-}, "Number.prototype.valueOf is not generic", TypeError);
+test(() => Number.prototype.valueOf.call({}),
+    "Number.prototype.valueOf requires that 'this' be a Number",
+    TypeError);
 
-test(function() {
-  Function.prototype.toString.call(1);
-}, "Function.prototype.toString is not generic", TypeError);
+test(() => Function.prototype.toString.call(1),
+    "Function.prototype.toString requires that 'this' be a Function",
+    TypeError);
 
 // kNotTypedArray
 test(function() {