tests/cases/compiler/derivedClassOverridesPrivateFunction1.ts(8,7): error TS2415: Class 'DerivedClass' incorrectly extends base class 'BaseClass'. Types have separate declarations of a private property '_init'. ==== tests/cases/compiler/derivedClassOverridesPrivateFunction1.ts (1 errors) ==== class BaseClass { constructor() { this._init(); } private _init() { } } class DerivedClass extends BaseClass { ~~~~~~~~~~~~ !!! error TS2415: Class 'DerivedClass' incorrectly extends base class 'BaseClass'. !!! error TS2415: Types have separate declarations of a private property '_init'. constructor() { super(); } private _init() { } } new DerivedClass();