for-of loop does not loop (declarations clash in generated js)

[eekboom]

TypeScript Version: 2.1.4

Compiled with --target ES5.

Code

// A *self-contained* demonstration of the problem follows...
class Main {

	constructor() {
		this.register("a", "b", "c");
	}

	private register(...names: string[]): void {
		for(let name of names) {
			console.log(name);

			this.bar({
				[name + ".a"]: () => { this.foo(name); },
			});
		}
	}

	private bar(a: any): void {}

	private foo(name: string): void {}

}

new Main();

Expected behavior:
Code prints "a", "b", and "c" on three lines
Actual behavior:
Code prints only a single line containing "a".

The bug only occurs when using both a Rest parameter ("...names") and the computed property name ([name + ".a"]) and a for-of loop and the arrow function in the loop body.

When I look at the generated JS I can see that there is a clash in variable declaration in the for-loop and the loop-body that has been extracted into a function.

TypeScript 2.1.5 gives correct output, but I have not found any explicit bug that is supposed to fix this behavior. So I am afraid that it was fixed only as a side effect of some other change and might break again in the future.
Could you include a test case like this?

[mhegazy]

This is fixed by #12831. Test added in #13946