Address code review

src/compiler/checker.ts

@@ -4915,7 +4915,7 @@ module ts {
                 container = getThisContainer(container, /* includeArrowFunctions */ false);
 
                 // When targeting es6, arrow function lexically bind "this" so we do not need to do the work of binding "this" in emitted code
-                needToCaptureLexicalThis = !(compilerOptions.target >= ScriptTarget.ES6);
+                needToCaptureLexicalThis = (languageVersion < ScriptTarget.ES6);
             }
 
             switch (container.kind) {

src/compiler/emitter.ts

@@ -1487,7 +1487,6 @@ module ts {
 
     // targetSourceFile is when users only want one file in entire project to be emitted. This is used in compilerOnSave feature
     export function emitFiles(resolver: EmitResolver, host: EmitHost, targetSourceFile?: SourceFile): EmitResult {
-        // var program = resolver.getProgram();
         var compilerOptions = host.getCompilerOptions();
         var languageVersion = compilerOptions.target || ScriptTarget.ES3;
         var sourceMapDataList: SourceMapData[] = compilerOptions.sourceMap ? [] : undefined;
@@ -3241,7 +3240,7 @@ module ts {
             }
 
             function shouldEmitAsArrowFunction(node: FunctionLikeDeclaration): boolean {
-                return node.kind === SyntaxKind.ArrowFunction && compilerOptions.target >= ScriptTarget.ES6;
+                return node.kind === SyntaxKind.ArrowFunction && languageVersion >= ScriptTarget.ES6;
             }
 
             function emitFunctionDeclaration(node: FunctionLikeDeclaration) {