diff --git a/modules/@angular/compiler/src/expression_parser/lexer.ts b/modules/@angular/compiler/src/expression_parser/lexer.ts
index 6dfa49e017..b8b6777aaa 100644
--- a/modules/@angular/compiler/src/expression_parser/lexer.ts
+++ b/modules/@angular/compiler/src/expression_parser/lexer.ts
@@ -25,10 +25,10 @@ const KEYWORDS = ['var', 'let', 'null', 'undefined', 'true', 'false', 'if', 'els
 
 @Injectable()
 export class Lexer {
-  tokenize(text: string): any[] {
-    var scanner = new _Scanner(text);
-    var tokens: Token[] = [];
-    var token = scanner.scanToken();
+  tokenize(text: string): Token[] {
+    const scanner = new _Scanner(text);
+    const tokens: Token[] = [];
+    let token = scanner.scanToken();
     while (token != null) {
       tokens.push(token);
       token = scanner.scanToken();
@@ -43,43 +43,40 @@ export class Token {
       public strValue: string) {}
 
   isCharacter(code: number): boolean {
-    return (this.type == TokenType.Character && this.numValue == code);
+    return this.type == TokenType.Character && this.numValue == code;
   }
 
-  isNumber(): boolean { return (this.type == TokenType.Number); }
+  isNumber(): boolean { return this.type == TokenType.Number; }
 
-  isString(): boolean { return (this.type == TokenType.String); }
+  isString(): boolean { return this.type == TokenType.String; }
 
   isOperator(operater: string): boolean {
-    return (this.type == TokenType.Operator && this.strValue == operater);
+    return this.type == TokenType.Operator && this.strValue == operater;
   }
 
-  isIdentifier(): boolean { return (this.type == TokenType.Identifier); }
+  isIdentifier(): boolean { return this.type == TokenType.Identifier; }
 
-  isKeyword(): boolean { return (this.type == TokenType.Keyword); }
+  isKeyword(): boolean { return this.type == TokenType.Keyword; }
 
   isKeywordDeprecatedVar(): boolean {
-    return (this.type == TokenType.Keyword && this.strValue == 'var');
+    return this.type == TokenType.Keyword && this.strValue == 'var';
   }
 
-  isKeywordLet(): boolean { return (this.type == TokenType.Keyword && this.strValue == 'let'); }
+  isKeywordLet(): boolean { return this.type == TokenType.Keyword && this.strValue == 'let'; }
 
-  isKeywordNull(): boolean { return (this.type == TokenType.Keyword && this.strValue == 'null'); }
+  isKeywordNull(): boolean { return this.type == TokenType.Keyword && this.strValue == 'null'; }
 
   isKeywordUndefined(): boolean {
-    return (this.type == TokenType.Keyword && this.strValue == 'undefined');
+    return this.type == TokenType.Keyword && this.strValue == 'undefined';
   }
 
-  isKeywordTrue(): boolean { return (this.type == TokenType.Keyword && this.strValue == 'true'); }
+  isKeywordTrue(): boolean { return this.type == TokenType.Keyword && this.strValue == 'true'; }
 
-  isKeywordFalse(): boolean { return (this.type == TokenType.Keyword && this.strValue == 'false'); }
+  isKeywordFalse(): boolean { return this.type == TokenType.Keyword && this.strValue == 'false'; }
 
   isError(): boolean { return this.type == TokenType.Error; }
 
-  toNumber(): number {
-    // -1 instead of NULL ok?
-    return (this.type == TokenType.Number) ? this.numValue : -1;
-  }
+  toNumber(): number { return this.type == TokenType.Number ? this.numValue : -1; }
 
   toString(): string {
     switch (this.type) {
diff --git a/modules/@angular/compiler/test/expression_parser/lexer_spec.ts b/modules/@angular/compiler/test/expression_parser/lexer_spec.ts
index 2107ddf0c1..9372a8b872 100644
--- a/modules/@angular/compiler/test/expression_parser/lexer_spec.ts
+++ b/modules/@angular/compiler/test/expression_parser/lexer_spec.ts
@@ -8,47 +8,45 @@
 
 import {Lexer, Token} from '@angular/compiler/src/expression_parser/lexer';
 
-import {StringWrapper} from '../../src/facade/lang';
-
 function lex(text: string): any[] {
   return new Lexer().tokenize(text);
 }
 
-function expectToken(token: any, index: any) {
+function expectToken(token: any, index: number) {
   expect(token instanceof Token).toBe(true);
   expect(token.index).toEqual(index);
 }
 
-function expectCharacterToken(token: any, index: any, character: any) {
+function expectCharacterToken(token: any, index: number, character: string) {
   expect(character.length).toBe(1);
   expectToken(token, index);
-  expect(token.isCharacter(StringWrapper.charCodeAt(character, 0))).toBe(true);
+  expect(token.isCharacter(character.charCodeAt(0))).toBe(true);
 }
 
-function expectOperatorToken(token: any, index: any, operator: any) {
+function expectOperatorToken(token: any, index: number, operator: string) {
   expectToken(token, index);
   expect(token.isOperator(operator)).toBe(true);
 }
 
-function expectNumberToken(token: any, index: any, n: any) {
+function expectNumberToken(token: any, index: number, n: number) {
   expectToken(token, index);
   expect(token.isNumber()).toBe(true);
   expect(token.toNumber()).toEqual(n);
 }
 
-function expectStringToken(token: any, index: any, str: any) {
+function expectStringToken(token: any, index: number, str: string) {
   expectToken(token, index);
   expect(token.isString()).toBe(true);
   expect(token.toString()).toEqual(str);
 }
 
-function expectIdentifierToken(token: any, index: any, identifier: any) {
+function expectIdentifierToken(token: any, index: number, identifier: string) {
   expectToken(token, index);
   expect(token.isIdentifier()).toBe(true);
   expect(token.toString()).toEqual(identifier);
 }
 
-function expectKeywordToken(token: any, index: any, keyword: any) {
+function expectKeywordToken(token: any, index: number, keyword: string) {
   expectToken(token, index);
   expect(token.isKeyword()).toBe(true);
   expect(token.toString()).toEqual(keyword);
@@ -213,12 +211,6 @@ export function main() {
         expectNumberToken(tokens[0], 0, 0.5);
       });
 
-      // NOTE(deboer): NOT A LEXER TEST
-      //    it('should tokenize negative number', () => {
-      //      var tokens:Token[] = lex("-0.5");
-      //      expectNumberToken(tokens[0], 0, -0.5);
-      //    });
-
       it('should tokenize number with exponent', function() {
         var tokens: Token[] = lex('0.5E-10');
         expect(tokens.length).toEqual(1);