Type union comes out as "any"

[danvk]

If I add this to expectType.ts.lint:

// $ExpectType "foo" | "bar"
declare let t: 'foo' | 'bar';

and run npm run build && npm run test, then I get the following error:

  // $ExpectType "foo" | "bar"
  declare let t: 'foo' | 'bar';

- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [Expected type to be:
-   "foo" | "bar"
- got:
-   any]

Somehow the type union gets converted to "any". Putting that same code in the TypeScript playground shows that TS understands the type correctly. I'm not sure what's going on here.

[danvk]

Here are a few variations that do work:

function test(t: 'foo' | 'bar') {
  t; // $ExpectType "foo" | "bar"
}

let t: 'foo' | 'bar';
t;  // $ExpectType "foo" | "bar"

So I guess you just can't do a type assertion on the line in which a variable is declared? It has to be on an expression?