No narrowing on assignment to this. union property #28763

export class ModelBase {
  modelBaseProp: boolean;

  constructor() {
  }
}

export class Model1 extends ModelBase {
  model1Prop?: number;

  constructor() {
    super();
  }
}

export class Model2 extends ModelBase {
  model2Prop?: string;

  constructor() {
    super();
  }
}

export class Test {
  test: Model1 | Model2;
  constructor() {
    this.test = new Model1();
    this.test.model1Prop = 1;

    this.test = new Model2();
    this.test.model2Prop = 'test';
  }
}

export class Model1 {
  model1Prop?: number;

  constructor() {
  }
}

export class Model2 {
  model2Prop?: string;

  constructor() {
  }
}

export class Test {
  test: Model1 | Model2;
  constructor() {
    this.test = new Model1();
    this.test.model1Prop = 1;

    this.test = new Model2();
    this.test.model2Prop = 'test';
  }
}