dart2js: Fix hints in code base.

pkg/compiler/lib/src/ssa/optimize.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.
 
 part of ssa;
 
 abstract class OptimizationPhase {
   String get name;
   void visitGraph(HGraph graph);
 }
@@ skipping 408 matching lines @@
     // Return types on native methods don't need to be checked, since the
     // declaration has to be truthful.
 
     // The call site might omit optional arguments. The inlined code must
     // preserve the number of arguments, so check only the actual arguments.
 
     List<HInstruction> inputs = node.inputs.sublist(1);
     int inputPosition = 1;  // Skip receiver.
     bool canInline = true;
     signature.forEachParameter((ParameterElement element) {
-      if (inputPosition < inputs.length && canInline) {
-        HInstruction input = inputs[inputPosition++];
+      if (inputPosition++ < inputs.length && canInline) {
         DartType type = element.type.unalias(compiler);
         if (type is FunctionType) {
           canInline = false;
         }
         if (compiler.enableTypeAssertions) {
           // TODO(sra): Check if [input] is guaranteed to pass the parameter
           // type check.  Consider using a strengthened type check to avoid
           // passing `null` to primitive types since the native methods usually
           // have non-nullable primitive parameter types.
           canInline = false;
@@ skipping 249 matching lines @@
         return graph.addConstantBool(true, compiler);
       } else if (expressionMask.intersection(typeMask,
                                              compiler.world).isEmpty) {
         return graph.addConstantBool(false, compiler);
       }
     }
     return node;
   }
 
   HInstruction visitTypeConversion(HTypeConversion node) {
-    HInstruction value = node.inputs[0];
     DartType type = node.typeExpression;
     if (type != null) {
       if (type.isMalformed) {
         // Malformed types are treated as dynamic statically, but should
         // throw a type error at runtime.
         return node;
       }
       if (!type.treatAsRaw || type.isTypeVariable) {
         return node;
       }
@@ skipping 1588 matching lines @@
 
     keyedValues.forEach((receiver, values) {
       result.keyedValues[receiver] =
           new Map<HInstruction, HInstruction>.from(values);
     });
 
     result.nonEscapingReceivers.addAll(nonEscapingReceivers);
     return result;
   }
 }