ExpectType should allow subtypes

[danvk]

This test:

'hello'  // $ExpectType string

currently triggers this error:

Expected type
  string
but got:
  "hello"

The type "hello" extends string, so this should be allowed. If you really want to check that the type is "hello", then you should write // $ExpectType "hello".

[danvk]

This is blocked on the TypeScript API exposing assignability checks.

[amir-arad]

pseudo solvable by injecting a line with half of an assignment above the tested line.
so

'hello'  // $ExpectType string

is transformed to

const c1: string =  
'hello' 

and the we're left with line numbers and error translation.

Maybe use a different marker, say, // $ExpectAsType ?