Discriminate union inference inconsistent behavior with if/else checks #36777

type TestA = {
  type: 'testA';
  bananas: 3;
};

type TestB = {
  type: 'testB';
  apples: 5;
};

type AllTests = TestA | TestB;

type MapOfAllTests = Record<string, AllTests>;

const doTestingStuff = (mapOfTests: MapOfAllTests, ids: string[]) => {
  ids.forEach(id => {
    // if we type this as "AllTests" instead of leaving it non-typed, the compiler warning
    // below also disappears..!?
    let test;
    test = mapOfTests[id];

    // at this point, TS considers "test" to be "AllTests",
    // so, discriminate union tests should work..?
    if (test.type === 'testA') {
      //  Property 'bananas' does not exist on type 'AllTests'.
      //    - Property 'bananas' does not exist on type 'TestB'.
      console.log(test.bananas);
    }
    switch (test.type) {
      case 'testA': {
       // no compiler warning
        console.log(test.bananas);
      }
    }
  });
};