Throwing type check errors is very slow compared to other checks (e.g., value check error in typed …

tests/standalone/byte_array_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Dart test program for testing native byte arrays.
 
 // Library tag to be able to run in html test framework.
 #library("ByteArrayTest.dart");
 
 #import('dart:scalarlist');
 
 void testCreateByteArray() {
   Uint8List byteArray;
 
   byteArray = new Uint8List(0);
   Expect.equals(0, byteArray.length);
 
   byteArray = new Uint8List(10);
   Expect.equals(10, byteArray.length);
   for (int i = 0; i < 10; i++) {
     Expect.equals(0, byteArray[i]);
   }
 
 }
 
-void testUnsignedByteArrayRange() {
+void testUnsignedByteArrayRange(bool check_throws) {
   Uint8List byteArray;
   byteArray = new Uint8List(10);
 
   byteArray[1] = 255;
   Expect.equals(255, byteArray[1]);
   byteArray[1] = 0;
   Expect.equals(0, byteArray[1]);
 
-  Expect.throws(() {
-    byteArray[1] = 1.2;
-  });
   // These should eventually throw.
   byteArray[1] = 256;
   byteArray[1] = -1;
   byteArray[2] = -129;
+  if (check_throws) {
+    Expect.throws(() {
+      byteArray[1] = 1.2;
+    });
+  }
 }
 
-void testByteArrayRange() {
+void testByteArrayRange(bool check_throws) {
   Int8List byteArray;
   byteArray = new Int8List(10);
   byteArray[1] = 0;
   Expect.equals(0, byteArray[1]);
   byteArray[2] = -128;
   Expect.equals(-128, byteArray[2]);
   byteArray[3] = 127;
   Expect.equals(127, byteArray[3]);
-  Expect.throws(() {
-    byteArray[1] = 1.2;
-  });
   // This should eventually throw.
   byteArray[0] = 128;
   byteArray[4] = -129;
+  if (check_throws) {
+    Expect.throws(() {
+      byteArray[1] = 1.2;
+    });
+  }
 }
 
 void testSetRange() {
   Uint8List byteArray = new Uint8List(3);
 
   List<int> list = [10, 11, 12];
   byteArray.setRange(0, 3, list);
   for (int i = 0; i < 3; i++) {
     Expect.equals(10 + i, byteArray[i]);
   }
@@ skipping 82 matching lines @@
     Expect.throws(() => array.subByteArray(0, "5"), (e) => e is ArgumentError);
     Expect.throws(() => array.subByteArray("0", 5), (e) => e is ArgumentError);
     Expect.throws(() => array.subByteArray("0"), (e) => e is ArgumentError);
   }
   Expect.throws(() => array.subByteArray(null), (e) => e is ArgumentError);
 }
 
 main() {
   for (int i = 0; i < 2000; i++) {
     testCreateByteArray();
-    testByteArrayRange();
-    testUnsignedByteArrayRange();
+    testByteArrayRange(false);
+    testUnsignedByteArrayRange(false);
     testSetRange();
     testIndexOutOfRange();
     testIndexOf();
     testSubArray();
   }
+  testByteArrayRange(true);
+  testUnsignedByteArrayRange(true);
 }