Responded to CR feedback.

src/compiler/parser.ts

@@ -323,7 +323,9 @@ module ts {
                 sys.writeFile(fileName, data, writeByteOrderMark);
             }
             catch (e) {
-                if (onError) onError(e.message);
+                if (onError) {
+                    onError(e.message);
+                }
             }
         }
 
@@ -405,14 +407,13 @@ module ts {
 
     function isEvalOrArgumentsIdentifier(node: Node): boolean {
         return node.kind === SyntaxKind.Identifier &&
-            (<Identifier>node).text &&
             ((<Identifier>node).text === "eval" || (<Identifier>node).text === "arguments");
     }
 
     /// Should be called only on prologue directives (isPrologueDirective(node) should be true)
     function isUseStrictPrologueDirective(node: Node): boolean {
         Debug.assert(isPrologueDirective(node));
-        return (<Identifier>(<ExpressionStatement>node).expression).text === "use strict";
+        return getTextOfNode((<ExpressionStatement>node).expression) === '"use strict"';
     }
 
     export function createSourceFile(filename: string, sourceText: string, languageVersion: ScriptTarget, version: string, isOpen: boolean = false): SourceFile {

src/compiler/utilities.ts

@@ -90,7 +90,9 @@ module ts {
     }
 
     export function getSourceFileOfNode(node: Node): SourceFile {
-        while (node && node.kind !== SyntaxKind.SourceFile) node = node.parent;
+        while (node && node.kind !== SyntaxKind.SourceFile) {
+            node = node.parent;
+        }
         return <SourceFile>node;
     }
 
@@ -161,7 +163,7 @@ module ts {
         node = getErrorSpanForNode(node);
         var file = getSourceFileOfNode(node);
 
-        var start = getFullWidth(node) === 0 ? node.pos : skipTrivia(file.text, node.pos);
+        var start = getTokenPosOfNode(node, file);
         var length = node.end - start;
 
         return createFileDiagnostic(file, start, length, message, arg0, arg1, arg2);