Address PR feedback

Author: JsonFreeman

src/compiler/checker.ts

@@ -2452,20 +2452,21 @@ module ts {
  return result;
  }
 
- function getBaseTypes(type: InterfaceType): ObjectType[] {
- if (!(<InterfaceTypeWithBaseTypes>type).baseTypes) {
+ function getBaseTypes(type: InterfaceType): ObjectType[]{
+ let typeWithBaseTypes = <InterfaceTypeWithBaseTypes>type;
+ if (!typeWithBaseTypes.baseTypes) {
  if (type.symbol.flags & SymbolFlags.Class) {
- resolveBaseTypesOfClass(<InterfaceTypeWithBaseTypes>type);
+ resolveBaseTypesOfClass(typeWithBaseTypes);
  }
  else if (type.symbol.flags & SymbolFlags.Interface) {
- resolveBaseTypesOfInterface(<InterfaceTypeWithBaseTypes>type);
+ resolveBaseTypesOfInterface(typeWithBaseTypes);
  }
  else {
  Debug.fail("type must be class or interface");
  }
  }
 
- return (<InterfaceTypeWithBaseTypes>type).baseTypes;
+ return typeWithBaseTypes.baseTypes;
  }
 
  function resolveBaseTypesOfClass(type: InterfaceTypeWithBaseTypes): void {
@@ -2492,9 +2493,9 @@ module ts {
 
  function resolveBaseTypesOfInterface(type: InterfaceTypeWithBaseTypes): void {
  type.baseTypes = [];
- forEach(type.symbol.declarations, declaration => {
+ for (let declaration of type.symbol.declarations) {
  if (declaration.kind === SyntaxKind.InterfaceDeclaration && getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration)) {
- forEach(getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration), node => {
+ for (let node of getInterfaceBaseTypeNodes(<InterfaceDeclaration>declaration)) {
  let baseType = getTypeFromHeritageClauseElement(node);
 
  if (baseType !== unknownType) {
@@ -2510,9 +2511,9 @@ module ts {
  error(node, Diagnostics.An_interface_may_only_extend_a_class_or_another_interface);
  }
  }
- });
+ }
  }
- });
+ }
  }
 
  function getDeclaredTypeOfClass(symbol: Symbol): InterfaceType {
@@ -2674,13 +2675,13 @@ module ts {
  let baseTypes = getBaseTypes(type);
  if (baseTypes.length) {
  members = createSymbolTable(type.declaredProperties);
- forEach(baseTypes, baseType => {
+ for (let baseType of baseTypes) {
  addInheritedMembers(members, getPropertiesOfObjectType(baseType));
  callSignatures = concatenate(callSignatures, getSignaturesOfType(baseType, SignatureKind.Call));
  constructSignatures = concatenate(constructSignatures, getSignaturesOfType(baseType, SignatureKind.Construct));
  stringIndexType = stringIndexType || getIndexTypeOfType(baseType, IndexKind.String);
  numberIndexType = numberIndexType || getIndexTypeOfType(baseType, IndexKind.Number);
- });
+ }
  }
  setObjectTypeMembers(type, members, callSignatures, constructSignatures, stringIndexType, numberIndexType);
  }
@@ -10148,7 +10149,7 @@ module ts {
 
  function checkInheritedPropertiesAreIdentical(type: InterfaceType, typeNode: Node): boolean {
  let baseTypes = getBaseTypes(type);
- if (!baseTypes.length || baseTypes.length === 1) {
+ if (baseTypes.length < 2) {
  return true;
  }