Fails to extend a class declared in condition if another function creates an instance of it

[peaBerberian]

TypeScript Version: 2.6.1

Code

class A {}
if (true) {
  class B extends A {}

  const foo = function () {
    new B();
  }
}

Expected behavior:

Should work as intended.

Actual behavior:

This translates into:

var __extends = (this && this.__extends) || (function () {
    var extendStatics = Object.setPrototypeOf ||
        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
    return function (d, b) {
        extendStatics(d, b);
        function __() { this.constructor = d; }
        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
    };
})();
var A = /** @class */ (function () {
    function A() {
    }
    return A;
}());
if (true) {
    var B_1 = /** @class */ (function (_super) {
        __extends(B_1, _super);
        function B() {
            return _super !== null && _super.apply(this, arguments) || this;
        }
        return B;
    }(A));
    var foo = function () {
        new B_1();
    };
}

This is problematic, especially the following line towards the end:

        __extends(B_1, _super);

B, the "constructor" should be extended. Not B_1, the "class" (which has a different name here for some reason, maybe that's part of the problem) as B_1 is not yet defined here.

This causes the parsing to fail.

[peaBerberian]

For others with the same problem, I can confirm that - from the previous example - renaming every B to B_1 in the transpiled js file, as ugly and bothersome as it sounds, fixes the issue.

Thanks for considering this issue by the way !