tests/cases/compiler/intrinsics.ts(2,21): error TS2304: Cannot find name 'hasOwnProperty'. tests/cases/compiler/intrinsics.ts(2,21): error TS4025: Exported variable 'hasOwnProperty' has or is using private name 'hasOwnProperty'. tests/cases/compiler/intrinsics.ts(11,1): error TS2304: Cannot find name '__proto__'. ==== tests/cases/compiler/intrinsics.ts (3 errors) ==== var hasOwnProperty: hasOwnProperty; // Error ~~~~~~~~~~~~~~ !!! error TS2304: Cannot find name 'hasOwnProperty'. ~~~~~~~~~~~~~~ !!! error TS4025: Exported variable 'hasOwnProperty' has or is using private name 'hasOwnProperty'. module m1 { export var __proto__; interface __proto__ {} class C { } } __proto__ = 0; // Error, __proto__ not defined ~~~~~~~~~ !!! error TS2304: Cannot find name '__proto__'. m1.__proto__ = 0; class Foo<__proto__> { } var foo: (__proto__: number) => void;