Fix most warnings and other minor cleanups.

lib/compiler/implementation/ssa/codegen.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.
 
 class SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name() => 'SSA code generator';
@@ skipping 483 matching lines @@
 
     // Check that the operation is one of +, *, - or /. Record whether
     // or not the operation is commutative.
     var isCommutative = false;
     if (instruction is HAdd || instruction is HMultiply) {
       isCommutative = true;
     } else if (instruction is !HSubtract && instruction is !HDivide) {
       return false;
     }
 
+    HBinaryArithmetic binary = instruction;
+    assert(binary.inputs.length == 3);
     // Is it a builtin operation involving constant numbers?
-    if (instruction.builtin && instruction.inputs.length == 3) {
-      var left = instruction.inputs[1];
-      var right = instruction.inputs[2];
+    if (binary.builtin) {
+      var left = binary.left;
+      var right = binary.right;
       if (left.isConstantNumber() && isCommutative) {
         var tmp = right;
         right = left;
         left = tmp;
       } else if (!right.isConstantNumber()) {
         return false;
       }
       // Right is constant number.
-      var value = right.constant.value;
+      HConstant constantRight = right;
+      NumConstant numberConstant = constantRight.constant;
+      num value = numberConstant.value;
       // Check that left has the same name as the definition and emit
       // the short update definition if it is.
       if (variableNames.getName(left) == name) {
-        if (instruction is HAdd && right.constant.value == 1) {
+        if (binary is HAdd && value == 1) {
           buffer.add('++');
           declareVariable(name);
-        } else if (instruction is HSubtract && right.constant.value == 1) {
+        } else if (binary is HSubtract && value == 1) {
           buffer.add('--');
           declareVariable(name);
         } else {
-          var operation = instruction.operation.name;
+          var operation = binary.operation.name;
           declareVariable(name);
           buffer.add(' ${operation}= ${value}');
         }
         return true;
       }
     }
     return false;
   }
 
   // For simple type checks like i = intTypeCheck(i), we don't have to
@@ skipping 1936 matching lines @@
   }
 
   int maxBailoutParameters;
 
   HBasicBlock beginGraph(HGraph graph) => graph.entry;
   void endGraph(HGraph graph) {}
 
   void bailout(HTypeGuard guard, String reason) {
     if (maxBailoutParameters === null) {
       maxBailoutParameters = 0;
-      work.guards.forEach((HTypeGuard guard) {
-        int inputLength = guard.inputs.length;
+      work.guards.forEach((HTypeGuard workGuard) {
+        int inputLength = workGuard.inputs.length;
         if (inputLength > maxBailoutParameters) {
           maxBailoutParameters = inputLength;
         }
       });
     }
     HInstruction input = guard.guarded;
     Namer namer = compiler.namer;
     Element element = work.element;
     buffer.add('return ');
     if (element.isInstanceMember()) {
@@ skipping 398 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }