Address code review

Author: Yui T

src/compiler/checker.ts

@@ -4856,7 +4856,7 @@ module ts {
             // To avoid that we will give an error to users if they use arguments objects in arrow function so that they
             // can explicitly bound arguments objects
             if (symbol === argumentsSymbol && getContainingFunction(node).kind === SyntaxKind.ArrowFunction) {
-              error(node, Diagnostics.An_argument_object_has_different_behaviour_across_Javascript_versions_Use_function_expression_or_rest_parameters_instead);
+              error(node, Diagnostics.The_argument_object_has_different_behaviour_across_Javascript_versions_Use_function_expression_or_rest_parameters_instead);
             }
 
             if (symbol.flags & SymbolFlags.Import) {
@@ -4915,12 +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
-                if (compilerOptions.target >= ScriptTarget.ES6) {
-                    needToCaptureLexicalThis = false;
-                }
-                else {
-                    needToCaptureLexicalThis = true;
-                }
+                needToCaptureLexicalThis = !(compilerOptions.target >= ScriptTarget.ES6);
             }
 
             switch (container.kind) {

src/compiler/diagnosticInformationMap.generated.ts

@@ -452,6 +452,6 @@ module ts {
         You_cannot_rename_this_element: { code: 8000, category: DiagnosticCategory.Error, key: "You cannot rename this element." },
         yield_expressions_are_not_currently_supported: { code: 9000, category: DiagnosticCategory.Error, key: "'yield' expressions are not currently supported.", isEarly: true },
         Generators_are_not_currently_supported: { code: 9001, category: DiagnosticCategory.Error, key: "Generators are not currently supported.", isEarly: true },
-        An_argument_object_has_different_behaviour_across_Javascript_versions_Use_function_expression_or_rest_parameters_instead: { code: 9002, category: DiagnosticCategory.Error, key: "An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead" },
+        The_argument_object_has_different_behaviour_across_Javascript_versions_Use_function_expression_or_rest_parameters_instead: { code: 9002, category: DiagnosticCategory.Error, key: "The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead" },
     };
 }

src/compiler/diagnosticMessages.json

@@ -1909,7 +1909,7 @@
 		"code": 9001,
 		"isEarly": true
 	},
-	"An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead": {
+	"The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead": {
 		"category": "Error",
 		"code": 9002
 	}

tests/baselines/reference/emitArrowFunctionWhenUsingArguments.errors.txt

@@ -1,37 +1,37 @@
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(2,15): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(7,19): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(13,13): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(19,15): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(2,15): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(7,19): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(13,13): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts(19,15): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
 
 
 ==== tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArguments.ts (4 errors) ====
     var a = () => {
         var arg = arguments[0];  // error
                   ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
     }
 
     var b = function () {
         var a = () => {
             var arg = arguments[0];  // error
                       ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
         }
     }
 
     function baz() {
     	() => {
     		var arg = arguments[0];
     		          ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
     	}
     }
 
     function foo(inputFunc: () => void) { }
     foo(() => {
         var arg = arguments[0];  // error
                   ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
     });
 
     function bar() {

tests/baselines/reference/emitArrowFunctionWhenUsingArgumentsES6.errors.txt

@@ -1,37 +1,37 @@
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(2,15): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(7,19): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(13,13): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
-tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(19,15): error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(2,15): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(7,19): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(13,13): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts(19,15): error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
 
 
 ==== tests/cases/conformance/es6/arrowFunction/emitArrowFunctionWhenUsingArgumentsES6.ts (4 errors) ====
     var a = () => {
         var arg = arguments[0];  // error
                   ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
     }
 
     var b = function () {
         var a = () => {
             var arg = arguments[0];  // error
                       ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
         }
     }
 
     function baz() {
     	() => {
     		var arg = arguments[0];
     		          ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
     	}
     }
 
     function foo(inputFunc: () => void) { }
     foo(() => {
         var arg = arguments[0];  // error
                   ~~~~~~~~~
-!!! error TS9002: An argument object has different behaviour across Javascript versions. Use function expression or rest parameters instead
+!!! error TS9002: The 'argument' object has different behaviour across Javascript versions. Use function expression or rest parameters instead
     });
 
     function bar() {