Make first and last getters.

lib/compiler/implementation/ssa/tracer.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.
 
 library tracer;
 
 import 'dart:io';
 import 'ssa.dart';
 import '../js_backend/js_backend.dart';
 import '../dart2jslib.dart';
@@ skipping 428 matching lines @@
     buf.add("Switch: (");
     buf.add(temporaryId(node.inputs[0]));
     buf.add(") ");
     for (int i = 1; i < node.inputs.length; i++) {
       buf.add(temporaryId(node.inputs[i]));
       buf.add(": B");
       buf.add(node.block.successors[i - 1].id);
       buf.add(", ");
     }
     buf.add("default: B");
-    buf.add(node.block.successors.last().id);
+    buf.add(node.block.successors.last.id);
     return buf.toString();
   }
 
   String visitThis(HThis node) => "this";
 
   String visitThrow(HThrow node) => "Throw ${temporaryId(node.inputs[0])}";
 
   String visitTruncatingDivide(HTruncatingDivide node) {
     return visitInvokeStatic(node);
   }
 
   String visitTry(HTry node) {
     List<HBasicBlock> successors = currentBlock.successors;
     String tryBlock = 'B${successors[0].id}';
     String catchBlock = 'none';
     if (node.catchBlock != null) {
       catchBlock = 'B${successors[1].id}';
     }
 
     String finallyBlock = 'none';
     if (node.finallyBlock != null) {
       finallyBlock = 'B${node.finallyBlock.id}';
     }
 
     return "Try: $tryBlock, Catch: $catchBlock, Finally: $finallyBlock, "
-        "Join: B${successors.last().id}";
+        "Join: B${successors.last.id}";
   }
 
   String visitTypeGuard(HTypeGuard node) {
     String type;
     HType guardedType = node.guardedType;
     if (guardedType == HType.MUTABLE_ARRAY) {
       type = "mutable_array";
     } else if (guardedType == HType.READABLE_ARRAY) {
       type = "readable_array";
     } else if (guardedType == HType.EXTENDABLE_ARRAY) {
@@ skipping 38 matching lines @@
   }
 
   String visitTypeConversion(HTypeConversion node) {
     return "TypeConversion: ${temporaryId(node.checkedInput)} to ${node.type}";
   }
 
   String visitRangeConversion(HRangeConversion node) {
     return "RangeConversion: ${node.checkedInput}";
   }
 }