Implement type checking of list literals (issue 220).

runtime/lib/growable_array.dart

 // Copyright (c) 2011, 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.
 
 class GrowableObjectArray<T> implements List<T> {
   ObjectArray<T> backingArray;
 
   void copyFrom(List<Object> src, int srcStart, int dstStart, int count) {
     Arrays.copy(src, srcStart, this, dstStart, count);
   }
@@ skipping 29 matching lines @@
   void insertRange(int start, int length, [T initialValue = null]) {
     if (length == 0) {
       return;
     }
     if (length < 0) {
       throw new IllegalArgumentException("negative length $length");
     }
     if (start < 0 || start > this.length) {
       throw new IndexOutOfRangeException(start);
     }
-    if (this.length + length >= backingArray.length) {
+    if (this.length + length > backingArray.length) {
       grow(backingArray.length + length);
     }
     Arrays.copy(backingArray,
                 start,
                 backingArray,
                 start + length,
                 this.length - start);
     if (initialValue !== null) {
       for (int i = start; i < start + length; i++) {
         backingArray[i] = initialValue;
       }
     }
     this.length = this.length + length;
   }
 
   List<T> getRange(int start, int length) {
     if (length == 0) return [];
     Arrays.rangeCheck(this, start, length);
     List list = new List<T>();
     list.length = length;
     Arrays.copy(this, start, list, 0, length);
     return list;
   }
 
-  // The length of this growable array. It is always less than the
-  // length of the backing array.
+  // The length of this growable array. It is always less than or equal to the
+  // length of the backing array, which itself is always greater than 0, so that
+  // grow() does not have to check for a zero length backing array before
+  // doubling its size.
   int _length;
 
   GrowableObjectArray()
       : _length = 0, backingArray = new ObjectArray<T>(4) {}
 
   GrowableObjectArray.withCapacity(int capacity) {
     _length = 0;
     if (capacity <= 0) {
       capacity = 4;
     }
     backingArray = new ObjectArray<T>(capacity);
   }
 
-  GrowableObjectArray._usingArray(List<T> array) {
-    backingArray = array;
-    _length = array.length;
-    if (_length == 0) {
-      grow(4);
-    }
-  }
-
   factory GrowableObjectArray<T>.from(Collection<T> other) {
     List<T> result = new GrowableObjectArray<T>();
     result.addAll(other);
     return result;
   }
 
   int get length() {
     return _length;
   }
 
   void set length(int new_length) {
-    if (new_length >= backingArray.length) {
+    if (new_length > backingArray.length) {
       grow(new_length);
     } else {
       for (int i = new_length; i < _length; i++) {
         backingArray[i] = null;
       }
     }
     _length = new_length;
   }
 
   T operator [](int index) {
@@ skipping 120 matching lines @@
     if (!hasNext()) {
       throw const NoMoreElementsException();
     }
     return _array[_pos++];
   }
 
   final GrowableObjectArray<T> _array;
   int _pos;
 }