Return length passed instead of receiver to allow chained assignments like

test/mjsunit/array-length.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
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 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
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 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 var a = [0,1,2,3];
-a.length = 0;
+assertEquals(0, a.length = 0);
 
 assertEquals('undefined', typeof a[0]);
 assertEquals('undefined', typeof a[1]);
 assertEquals('undefined', typeof a[2]);
 assertEquals('undefined', typeof a[3]);
 
 
 var a = [0,1,2,3];
-a.length = 2;
+assertEquals(2, a.length = 2);
 
 assertEquals(0, a[0]);
 assertEquals(1, a[1]);
 assertEquals('undefined', typeof a[2]);
 assertEquals('undefined', typeof a[3]);
 
 
 var a = new Array();
 a[0] = 0;
 a[1000] = 1000;
 a[1000000] = 1000000;
 a[2000000] = 2000000;
 
 assertEquals(2000001, a.length);
-a.length = 0;
+assertEquals(0, a.length = 0);
 assertEquals(0, a.length);
 assertEquals('undefined', typeof a[0]);
 assertEquals('undefined', typeof a[1000]);
 assertEquals('undefined', typeof a[1000000]);
 assertEquals('undefined', typeof a[2000000]);
 
 
 var a = new Array();
 a[0] = 0;
 a[1000] = 1000;
 a[1000000] = 1000000;
 a[2000000] = 2000000;
 
 assertEquals(2000001, a.length);
-a.length = 2000;
+assertEquals(2000, a.length = 2000);
 assertEquals(2000, a.length);
 assertEquals(0, a[0]);
 assertEquals(1000, a[1000]);
 assertEquals('undefined', typeof a[1000000]);
 assertEquals('undefined', typeof a[2000000]);
 
 
 var a = new Array();
 a[Math.pow(2,31)-1] = 0;
 a[Math.pow(2,30)-1] = 0;
 assertEquals(Math.pow(2,31), a.length);
 
 
 var a = new Array();
 a[0] = 0;
 a[1000] = 1000;
 a[Math.pow(2,30)-1] = Math.pow(2,30)-1;
 a[Math.pow(2,31)-1] = Math.pow(2,31)-1;
 a[Math.pow(2,32)-2] = Math.pow(2,32)-2;
 
 assertEquals(Math.pow(2,30)-1, a[Math.pow(2,30)-1]);
 assertEquals(Math.pow(2,31)-1, a[Math.pow(2,31)-1]);
 assertEquals(Math.pow(2,32)-2, a[Math.pow(2,32)-2]);
 
 assertEquals(Math.pow(2,32)-1, a.length);
-a.length = Math.pow(2,30)+1;  // not a smi!
+assertEquals(Math.pow(2,30) + 1, a.length = Math.pow(2,30)+1);  // not a smi!
 assertEquals(Math.pow(2,30)+1, a.length);
 
 assertEquals(0, a[0]);
 assertEquals(1000, a[1000]);
 assertEquals(Math.pow(2,30)-1, a[Math.pow(2,30)-1]);
 assertEquals('undefined', typeof a[Math.pow(2,31)-1]);
 assertEquals('undefined', typeof a[Math.pow(2,32)-2], "top");
 
 
 var a = new Array();
-a.length = new Number(12);
+assertEquals(12, a.length = new Number(12));
 assertEquals(12, a.length);
 
 
 var o = { length: -23 };
 Array.prototype.pop.apply(o);
 assertEquals(4294967272, o.length);
+
+// Check case of compiled stubs.
+var a = [];
+for (var i = 0; i < 7; i++) {
+  assertEquals(3, a.length = 3);
+
+  var t = 239;
+  t = a.length = 7;
+  assertEquals(7, t);
+}